Digital information recording media and method of using same

ABSTRACT

A digital information recording media which includes a recording layer comprising a light-stable colored composition which composition is mutable or decolorizable upon exposure to a specific wavelength of ultraviolet radiation. The light-stable colored composition includes a colorant and an ultraviolet radiation transorber. The colorant, in the presence of the radiation transorber, is adapted, upon exposure of the transorber to specific, narrow bandwidth ultraviolet radiation, to be mutable. The radiation transorber also imparts light-stability to the colorant so that the colorant does not fade when exposed to sunlight or artificial light. The ultraviolet radiation transorber is adapted to absorb radiation and interact with the colorant to effect the irreversible mutation of the colorant. Especially useful radiation is incoherent, pulsed ultraviolet radiation produced by a dielectric barrier discharge excimer lamp or coherent, pulse radiation produced by an excimer laser. In another embodiment, the colored composition which comprises a colorant and an ultraviolet radiation transorber may also contain a molecular includant having a chemical structure which defines at least one cavity. Each of the colorant and radiation transorber is associated with the molecular includant. In some embodiments, the colorant is at least partially included within a cavity of the molecular includant and the ultraviolet radiation transorber is associated with the molecular includant outside of the cavity. In other embodiments, the radiation transorber is covalently coupled to the molecular includant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. Patentapplication Ser. No. 08/403,240, filed Mar. 10, 1995, now abandoned,which is incorporated herein by reference, which a continuation-in-partpatent application of U.S. Patent application Ser. No. 08/373,958, filedon Jan. 17, 1995, which is incorporated herein by reference, which is acontinuation-in-part of U.S. Patent application Ser. No. 08/360,501,filed on Dec. 21, 1994, which is incorporated herein by reference, andU.S. Patent application Ser. No. 08/359,670, filed on Dec. 20, 1994, nowabandoned, which is incorporated herein by reference, both of which arecontinuation-in-part patent applications of U.S. Patent application Ser.No. 08/336,813, filed Nov. 9, 1994, now abandoned, and U.S. Patentapplication Ser. No. 08/258,858, filed on Jun. 13, 1994, now abandoned,which is incorporated herein by reference, which is acontinuation-in-part patent application of U.S. Patent application Ser.No. 08/119,912, filed Sep. 10, 1993, now abandoned, which isincorporated herein by reference, and which is a continuation-in-partpatent application of U.S. Patent application Ser. No. 08/103,503, filedon Aug. 5, 1993, now abandoned, which is incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to digital information recording media,such as optical disks. The present invention more particularly relatesto digital information recording media which includes a recording layercomprising a mutable dye which layer is mutable or erasable uponexposure to a specific wavelength of ultraviolet radiation, but iscolor-stable in sunlight or artificial light. The present invention alsorelates to an improved method for recording digital information onrecording media. More particularly, the present invention relates to amethod of recording digital information on recording media having arecording layer comprising a mutable dye which layer is mutable orerasable by selectively exposing portions of the recording layer to aspecific wavelength of ultraviolet radiation, yet the unexposed portionsare color-stable in sunlight or artificial light.

BACKGROUND OF THE INVENTION

It is known in the art to create a digital recording medium comprising asubstrate having a layer of a colored, photobleachable compositionthereon. Information is recorded on the recording medium by selectivelyexposing portions of the recording medium to light to thereby initiate achemical reaction which results in decomposition of the coloring agentcontained therein. Examples of such prior art recording media aredisclosed in U.S. Pat. No. 5,312,713; U.S. Pat. No. 4,954,380 andJapanese patent application No. 01-342989 (the disclosures of which areall incorporated herein by reference). Examples of such digitalrecording media include, optical disks, such as compact discs, which area read-only, non-erasable media for storing information, such asdigitized music, video, computer data, and combinations thereof, andwritable optical disks, such as write once, read many times "WORMdisks."

U.S. Pat. No. 5,312,713 relates to an information recording medium, suchas an optical disk. The patent discloses a substrate upon which isdisposed a recording layer. The recording layer comprises a mixture oforganic polysilane and an oxo metallic phthalocyanine dye. Anultraviolet light source is selectively irradiated on portions of therecording layer. The irradiation causes a photo decomposition of theorganic polysilane. Then, the entire recording layer is heated to atemperature equal to or greater than the glass transition point of theorganic polysilane so that the decomposition product produced by thephotodecomposition contacts the oxo metallic phthalocyanine pigmentwhich causes the decoloring reaction of the pigment. Thereby, only theportion of the pigment in the recording layer which was irradiated bythe ultraviolet light is decolorized; the non-irradiated portion retainsit color. The information recorded on the recording layer can be read bydetecting the difference among the absorbency of each portion (i.e.,between irradiated and non-irradiated portions) by scanning therecording layer with low-energy laser beams.

U.S. Pat. No. 4,954,380 relates to an optical recording medium. Thispatent discloses a transparent substrate upon which is coated an opticalrecording layer which includes a bleachable organic dye which isbleachable under ultraviolet radiation, such as cyanine dyes, xanthenedyes and azine dyes. A photomask having a transparent tracking patternis then placed over the recording layer and the mask is irradiated withultraviolet light. The exposed portion of the recording layer isbleached due to photochemical decomposition of the organic dyes in therecording layer. As a result, there is formed in the recording layer atracking region having different optical characteristics from thenon-exposed region.

Japanese patent application No. 01-342989 relates to an opticalrecording medium. The recording medium comprises a base, a recordinglayer, a reflective layer and a protective coating layer. The recordinglayer comprises a coloring matter, such as a cyanine dye having amaximum absorbency of 600-900 nm, and a photobleachable coloring matter,such as an azo dye having a maximum absorbency of 350-600 nm.

A major problem with colorants used in information storage media, suchas optical disks, is that they tend to fade when exposed to sunlight orartificial light. It is believed that most of the fading of colorantswhen exposed to light is due to photodegradation mechanisms. Thesedegradation mechanisms include oxidation or reduction of the colorantsdepending upon the environmental conditions in which the colorant isplaced. Fading of a colorant also depends upon the substrate upon whichthey reside.

Product analysis of stable photoproducts and intermediates has revealedseveral important modes of photodecomposition. These include electronejection from the colorant, reaction with ground-state or excitedsinglet state oxygen, cleavage of the central carbon-phenyl ring bondsto form amino substituted benzophenones, such as triphenylmethane dyes,reduction to form the colorless leuco dyes and electron or hydrogen atomabstraction to form radical intermediates.

Various factors such as temperature, humidity, gaseous reactants,including O₂, O₃, SO₂, and NO₂, and water soluble, nonvolatilephotodegradation products have been shown to influence fading ofcolorants. The factors that effect colorant fading appear to exhibit acertain amount of interdependence. It is due to this complex behaviorthat observations for the fading of a particular colorant on aparticular substrate cannot be applied to colorants and substrates ingeneral.

Under conditions of constant temperature it has been observed that anincrease in the relative humidity of the atmosphere increases the fadingof a colorant for a variety of colorant-substrate systems (e.g.,McLaren, K., J. Soc. Dyers Colour, 1956, 72, 527). For example, as therelative humidity of the atmosphere increases, a fiber may swell becausethe moisture content of the fiber increases. This aids diffusion ofgaseous reactants through the substrate structure.

The ability of a light source to cause photochemical change in acolorant is also dependent upon the spectral distribution of the lightsource, in particular the proportion of radiation of wavelengths mosteffective in causing a change in the colorant and the quantum yield ofcolorant degradation as a function of wavelength. On the basis ofphotochemical principles, it would be expected that light of higherenergy (short wavelengths) would be more effective at causing fadingthan light of lower energy (long wavelengths). Studies have revealedthat this is not always the case. Over 100 colorants of differentclasses were studied and found that generally the most unstable werefaded more efficiently by visible light while those of higherlightfastness were degraded mainly by ultraviolet light (McLaren, K., J.Soc. Dyers Colour, 1956, 72, 86).

The influence of a substrate on colorant stability can be extremelyimportant. Colorant fading may be retarded or promoted by some chemicalgroup within the substrate. Such a group can be a ground-state speciesor an excited-state species. The porosity of the substrate is also animportant factor in colorant stability. A high porosity can promotefading of a colorant by facilitating penetration of moisture and gaseousreactants into the substrate. A substrate may also act as a protectiveagent by screening the colorant from light of wavelengths capable ofcausing degradation.

The purity of the substrate is also an important consideration wheneverthe photochemistry of dyed technical polymers is considered. Forexample, technical-grade cotton, viscose rayon, polyethylene,polypropylene, and polyisoprene are known to contain carbonyl groupimpurities. These impurities absorb light of wavelengths greater than300 nm, which are present in sunlight, and so, excitation of theseimpurities may lead to reactive species capable of causing colorantfading (van Beek, H.C.A., Col. Res. AppI., 1983, 8(3), 176).

Therefore, for all of these reasons, there exists a great need for adigital information recording medium and for a method of recordingdigital information on a recording medium which medium is more stable tothe effects of both sunlight and artificial light.

SUMMARY OF THE INVENTION

The present invention addresses the needs described above by providing arecording medium which is stabilized against radiation includingradiation in the visible wavelength range and in which the light-stablecolored recording layer is mutable by exposure to certain narrowbandwidths of radiation; particularly, ultraviolet radiation. Thus, thepresent invention provides a recording layer comprising a colorantwhich, in the presence of an ultraviolet radiation transorber, ismutable when exposed to a specific wavelength of ultraviolet radiation,while at the same time, provides light stability to the colorant whenthe composition is exposed to sunlight or artificial light.

Specifically, the recording layer of the present invention includes acolorant and a radiation transorber. When the recording layer of thepresent invention is exposed to sunlight or artificial light, thecolorant therein is stabilized so that it does not fade in the light.The radiation transorber may be any material which is adapted to absorbradiation and interact with the colorant to effect the mutation of thecolorant. Generally, the radiation transorber contains a photoreactorand a wavelength-specific sensitizer. The wavelength-specific sensitizergenerally absorbs radiation having a specific wavelength, and thereforea specific amount of energy, and transfers the energy to thephotoreactor. It is desirable that the mutation of the colorant beirreversible.

The present invention also relates to recording medium colorantcompositions having improved stability, wherein the colorant isassociated with a modified photoreactor. It has been determined thatconventional photoreactors, which normally contain a carbonyl group witha functional group on the carbon alpha to the carbonyl group, acquirethe ability to stabilize colorants when the functional group on thealpha carbon is removed via dehydration.

Accordingly, the present invention also includes a novel method ofdehydrating photoreactors that have a hydroxyl group in the alphaposition to a carbonyl group. This reaction is necessary to impart thecolorant stabilizing capability to the photoreactor. The novel method ofdehydrating photoreactors that have a hydroxyl group in the alphaposition to a carbonyl group can be used with a wide variety ofphotoreactors to provide the colorant stabilizing capability to thephotoreactor. The resulting modified photoreactor can optionally belinked to a wavelength-selective sensitizer to impart the capability ofdecolorizing a colorant when exposed to a predetermined narrowwavelength of electromagnetic radiation. Accordingly, the presentinvention provides a photoreactor capable of stabilizing a colorant withwhich it is admixed.

As stated above, the mixture of colorant and radiation transorber ismutable upon exposure to radiation. The photoreactor may or may not bemodified as described above to impart stability when admixed to acolorant. In one embodiment, an ultraviolet radiation transorber isadapted to absorb ultraviolet radiation and interact with the colorantto effect the irreversible mutation of the colorant. It is desirablethat the ultraviolet radiation transorber absorb ultraviolet radiationat a wavelength of from about 4 to about 300 nanometers. It is even moredesirable that the ultraviolet radiation transorber absorb ultravioletradiation at a wavelength of 100 to 300 nanometers. The colorant incombination with the ultraviolet radiation transorber remains stablewhen exposed to sunlight or artificial light. If the photoreactor ismodified as described above, the colorant has improved stability whenexposed to sunlight or artificial light.

In another embodiment of the present invention, the colored compositionof the present invention may also contain a molecular includant having achemical structure which defines at least one cavity. The molecularincludants include, but are not limited to, clathrates, zeolites, andcyclodextrins. Each of the colorant and ultraviolet radiation transorberor modified photoreactor can be associated with one or more molecularincludant. The includant can have multiple radiation transorbersassociated therewith (see co-pending U.S. Patent Application Ser. No.08/359,670, now abandoned). In other embodiments, the includant can havemany modified photoreactors associated therewith.

In some embodiments, the colorant is at least partially included withina cavity of the molecular includant and the ultraviolet radiationtransorber or modified photoreactor is associated with the molecularincludant outside of the cavity. In some embodiments, the ultravioletradiation transorber or modified photoreactor is covalently coupled tothe outside of the molecular includant.

The present invention also relates to a method of mutating the colorantassociated with the composition of the present invention. The methodcomprises irradiating a composition containing a mutable colorant and anultraviolet radiation transorber with ultraviolet radiation at a dosagelevel sufficient to mutate the colorant. As stated above, in someembodiments the composition further includes a molecular includant. Inanother embodiment, the composition is applied to a substrate beforebeing irradiated with ultraviolet radiation. It is deskable that themutated colorant is stable.

The present invention also relates to a method of recording informationon a recording medium comprising a colored recording layer. The coloredrecording layer comprises a colorant and a radiation transorber asdescribed above. Information is recorded on the recording layer bymutating the colorant in the colored recording layer of the presentinvention. The method comprises selectively irradiating the coloredrecording layer with ultraviolet radiation at a dosage level sufficientto mutate or erase (i.e., decolorize) the colorant. As stated above, insome embodiments the recording layer further includes a molecularincludant.

Accordingly, the present invention provides an improved informationrecording medium and an improved method of recording information. Also,the present invention provides an information recording medium having amutable colored recording layer thereon which layer is color-stable whenexposed to sunlight or artificial light. The present invention furtherprovides an information recording medium having a mutable coloredrecording layer thereon which layer can be selectively decolorized byexposure to a predetermined relatively narrow wavelength ofelectromagnetic radiation.

The present invention also provides an information recording mediumhaving a mutable colored recording layer thereon which layer does notrequire a complicated developing process. Further, the present inventionprovides an improved optical disk for recording digital information,such as music, video, computer data, and the like, which is relativelyeasy to fabricate.

These and other objects, features and advantages of the presentinvention will become apparent after a review of the following detaileddescription of the disclosed embodiments and the appended drawing andclaims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 illustrates an ultraviolet radiation transorber/mutablecolorant/molecular includant complex wherein the mutable colorant ismalachite green, the ultraviolet radiation transorber is IRGACURE 184(1-hydroxycyclohexyl phenyl ketone), and the molecular includant isβ-cyclodextrin.

FIG. 2 illustrates an ultraviolet radiation transorber/mutablecolorant/molecular includant complex wherein the mutable colorant isVictoria Pure Blue BO (Basic Blue 7), the ultraviolet radiationtransorber is IRGACURE 184 (1-hydroxycyclohexyl phenyl ketone), and themolecular includant is β-cyclodextrin.

FIG. 3 is a plot of the average number of ultraviolet radiationtransorber molecules which are covalently coupled to each molecule of amolecular includant in several colored compositions, which number alsois referred to by the term, "degree of substitution," versus thedecolorization time upon exposure to 222-nanometer excimer lampultraviolet radiation.

FIG. 4 is an illustration of several 222 nanometer excimer lampsarranged in four parallel columns wherein the twelve numbers representthe locations where twelve intensity measurements were obtainedapproximately 5.5 centimeters from the excimer lamps.

FIG. 5 is an illustration of several 222 nanometer excimer lampsarranged in four parallel columns wherein the nine numbers represent thelocations where nine intensity measurements were obtained approximately5.5 centimeters from the excimer lamps.

FIG. 6 is an illustration of several 222 nanometer excimer lampsarranged in four parallel columns wherein the location of the number "1"denotes the location where ten intensity measurements were obtained fromincreasing distances from the lamps at that location. (The measurementsand their distances from the lamp are summarized in Table 12.)

FIG. 7 is a plan view of a disclosed embodiment of an optical disc inaccordance with the present invention.

FIG. 8 is a cross-sectional schematic view of the optical disc shown inFIG. 7 taken along the line 2--2 and also showing a disclosed embodimentof the information recording/reading system of the present invention.

FIG. 9 is a cross-sectional schematic view of an alternate disclosedembodiment of the information recording/reading system of the presentinvention.

FIG. 10 is a partial detail view of the optical disk shown in FIG. 7.

FIG. 11 is a cross-sectional schematic view of an alternate disclosedembodiment of the information recording/reading system of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates in general to a light-stable colorantsystem that is mutable by exposure to narrow band-width ultravioletradiation and to a recording medium employing such a colorant system.The present invention more particularly relates to a compositioncomprising a colorant which, in the presence of a radiation transorber,is stable under ordinary light but is mutable when exposed to specific,narrow band-width radiation. The radiation transorber is capable ofabsorbing radiation and interacting with the colorant to effect amutation of the colorant. The radiation transorber may be any materialwhich is adapted to absorb radiation and interact with the colorant toeffect the mutation of the colorant. Generally, the radiation transorbercontains a photoreactor and a wavelength-specific sensitizer. Thewavelength-specific sensitizer generally absorbs radiation having aspecific wavelength, and therefore a specific amount of energy, andtransfers the energy to the photoreactor. It is desirable that themutation of the colorant be irreversible.

The present invention also relates to colorant compositions havingimproved stability, wherein the colorant is associated with a modifiedphotoreactor. It has been determined that conventional photoreactorswhich normally contain a carbonyl group with a functional group on thecarbon alpha to the carbonyl group acquire the ability to stabilizecolorants when the functional group on the alpha carbon is removed.Accordingly, the present invention also includes a novel method ofdehydrating photoreactors that have a hydroxyl group in the alphaposition to a carbonyl group. This reaction is necessary to impart thecolorant stabilizing capability to the photoreactor. The novel method ofdehydrating photoreactors that have a hydroxyl group in the alphaposition to a carbonyl group can be used with a wide variety ofphotoreactors to provide the colorant stabilizing capability to thephotoreactor. The resulting modified photoreactor can optionally belinked to wavelength-selective sensitizer to impart the capability ofdecolorizing a colorant when exposed to a predetermined narrowwavelength of electromagnetic radiation. Accordingly, the presentinvention provides a photoreactor capable of stabilizing a colorant thatit is admixed with.

In certain embodiments of the present invention, the colorant andradiation transorber is mutable upon exposure to radiation. In thisembodiment, the photoreactor may or may not be modified as describedabove to impart stability when admixed to a colorant. In one embodiment,an ultraviolet radiation transorber is adapted to absorb ultravioletradiation and interact with the colorant to effect the irreversiblemutation of the colorant. It is desirable that the ultraviolet radiationtransorber absorb ultraviolet radiation at a wavelength of from about 4to about 300 nanometers. If the photoreactor in the radiation transorberis modified as described above, the colorant has improved stability whenexposed to sunlight or artificial light.

The present invention also relates to a method of mutating the colorantin the composition of the present invention. The method comprisesirradiating a composition containing a mutable colorant and a radiationtransorber with radiation at a dosage level sufficient to mutate thecolorant.

The present invention further relates to a method of stabilizing acolorant comprising associating the modified photoreactor describedabove with the colorant. Optionally, the photoreactor may be associatedwith a wavelength-selective sensitizer, or the photoreactor may beassociated with a molecular includant, or both.

With reference to the drawing in which like number indicate likeelements throughout the several views, it will be seen that there is acompact disc 10 comprising a plastic substrate 12 and a recording layer14 disposed thereon.

The recording layer 14 comprises a colored composition comprising acolorant which, in the presence of a radiation transorber, is stableunder ordinary fight but is mutable when exposed to specific, narrowband-width radiation. Desirably, the radiation transorber is anultraviolet radiation transorber. The ultraviolet radiation transorberis capable of absorbing ultraviolet radiation and interacting with thecolorant to effect a mutation of the colorant. Optionally, a molecularincludant can be included in the composition which provides a moreefficient mutable colorant and a more stable colorant to sunlight andordinary artificial light.

The term "composition" and such variations as "colored composition" areused herein to mean a colorant, and a radiation transorber. A radiationtransorber is comprised of a photoreactor and a wavelength-selectivesensitizer. The photoreactor may be any of the photoreactors listedbelow, including conventional photoreactors, and modified photoreactorsas described below. When reference is being made to a coloredcomposition which is adapted for a specific application, the term"composition-based" is used as a modifier to indicate that the materialincludes a colorant, an ultraviolet radiation transorber, and,optionally, a molecular includant. Optionally, the material may includeother components as discussed below.

As used herein, the term "colorant" is meant to include, withoutlimitation, any material which, in the presence of a radiationtransorber, is adapted upon exposure to specific radiation to bemutable. The colorant will typically be an organic material, such as anorganic colorant or pigment. Desirably, the colorant will besubstantially transparent to, that is, will not significantly interactwith, the ultraviolet radiation to which it is exposed. The term ismeant to include a single material or a mixture of two or morematerials.

As used herein, the term "irreversible" means that the colorant will notrevert to its original color when it no longer is exposed to ultravioletradiation.

The term "radiation transorber" is used herein to mean any materialwhich is adapted to absorb radiation at a specific wavelength andinteract with the colorant to affect the mutation of the colorant and,at the same time, protect the colorant from fading in sunlight orartificial light. The term "ultraviolet radiation transorber" is usedherein to mean any material which is adapted to absorb ultravioletradiation and interact with the colorant to effect the mutation of thecolorant. In some embodiments, the ultraviolet radiation transorber maybe an organic compound. Where the radiation transorber is comprised of awavelength-selective sensitizer and a photoreactor, the photoreactor mayoptionally be modified as described below.

The radiation transorber, modified radiation transorber, and methods ofmaking and using the same, are described in U.S. Patent application Ser.No. 461,372, filed Jun. 5, 1995, which is hereby incorporated byreference.

The term "compound" is intended to include a single material or amixture of two or more materials. If two or more materials are employed,it is not necessary that all of them absorb radiation of the samewavelength. As discussed more fully below, a radiation transorber iscomprised of a photoreactor and a wavelength selective sensitizer. Theradiation transorber has the additional property of making the colorantwith which the radiation transorber is associated light stable tosunlight or artificial light.

The term "light-stable" is used herein to mean that the colorant, whenassociated with the radiation transorber or modified photoreactor, ismore stable to light, including, but not limited to, sunlight orartificial light, than when the colorant is not associated with thesecompounds.

The term "molecular includant," as used herein, is intended to mean anysubstance having a chemical structure which defines at least one cavity.That is, the molecular includant is a cavity-containing structure. Asused herein, the term "cavity" is meant to include any opening or spaceof a size sufficient to accept at least a portion of one or both of thecolorant and the ultraviolet radiation transorber.

The term "functionalized molecular includant" is used herein to mean amolecular includant to which one or more molecules of an ultravioletradiation transorber are covalently coupled to each molecule of themolecular includant. The term "degree of substitution" is used herein torefer to the number of these molecules or leaving groups (defined below)which are covalently coupled to each molecule of the molecularincludant.

The term "derivatized molecular includant" is used herein to mean amolecular includant having more than two leaving groups covalentlycoupled to each molecule of molecular includant. The term "leavinggroup" is used herein to mean any leaving group capable of participatingin a bimolecular nucleophilic substitution reaction.

The term "artificial light" is used herein to mean light having arelatively broad bandwidth that is produced from conventional lightsources, including, but not limited to, conventional incandescent lightbulbs and fluorescent light bulbs.

The term "ultraviolet radiation" is used herein to mean electromagneticradiation having wavelengths in the range of from about 4 to about 400nanometers. The especially desirable ultraviolet radiation range for thepresent invention is between approximately 100 to 375 nanometers. Thus,the term includes the regions commonly referred to as ultraviolet andvacuum ultraviolet. The wavelength ranges typically assigned to thesetwo regions are from about 180 to about 400 nanometers and from about100 to about 180 nanometers, respectively.

The term "thereon" is used herein to mean thereon or therein. Forexample, the present invention includes a substrate having a coloredcomposition thereon. According to the definition of "thereon" thecolored composition may be present on the substrate or it may be in thesubstrate.

The term "mutable," with reference to the colorant, is used to mean thatthe absorption maximum of the colorant in the visible region of theelectromagnetic spectrum is capable of being mutated or changed byexposure to radiation, desirably ultraviolet radiation, when in thepresence of the radiation transorber. In general, it is only necessarythat such absorption maximum be mutated to an absorption maximum whichis different from that of the colorant prior to exposure to theultraviolet radiation, and that the mutation be irreversible. Thus, thenew absorption maximum can be within or outside of the visible region ofthe electromagnetic spectrum. In other words, the colorant can mutate toa different color or be rendered colorless. The latter is also desirablewhen the colorant is used in data processing forms for use withphoto-sensing apparatus that detect the presence of indicia atindicia-receiving locations of the form.

In several embodiments, the radiation transorber molecule, thewavelength-selective sensitizer, or the photoreactor may be associatedwith a molecular includant. It is to be noted that in all the formulas,the number of such molecules can be between approximately 1 andapproximately 21 molecules per molecular includant. Of course, incertain situations, there can be more than 21 molecules per molecularincludant molecule. Desirably, there are more than three of suchmolecules per molecular includant.

The degree of substitution of the functionalized molecular includant maybe in a range of from 1 to approximately 21. As another example, thedegree of substitution may be in a range of from 3 to about 10. As afurther example, the degree of substitution may be in a range of fromabout 4 to about 9.

The colorant is associated with the functionalized molecular includant.The term "associated" in its broadest sense means that the colorant isat least in close proximity to the functionalized molecular includant.For example, the colorant may be maintained in close proximity to thefunctionalized molecular includant by hydrogen bonding, van der Waalsforces, or the like. Alternatively, the colorant may be covalentlybonded to the functionalized molecular includant, although this normallyis neither desired nor necessary. As a further example, the colorant maybe at least partially included within the cavity of the functionalizedmolecular includant.

The examples below disclose methods of preparing and associating thesecolorants and ultraviolet radiation transorbers to beta-cyclodextrins.For illustrative purposes only, Examples 1, 2, 6, and 7 disclose one ormore methods of preparing and associating colorants and ultravioletradiation transorbers to cyclodextrins.

In those embodiments of the present invention in which the ultravioletradiation transorber is covalently coupled to the molecular includant,the efficiency of energy transfer from the ultraviolet radiationtransorber to the colorant is, at least in part, a function of thenumber of ultraviolet radiation transorber molecules which are attachedto the molecular includant. It now is known that the synthetic methodsdescribed above result in covalently coupling an average of twotransorber molecules to each molecule of the molecular includant.Because the time required to mutate the colorant should, at least inpart, be a function of the number of ultraviolet radiation transorbermolecules coupled to each molecule of molecular includant, there is aneed for an improved colored composition in which an average of morethan two ultraviolet radiation transorber molecules are covalentlycoupled to each molecule of the molecular includant.

Accordingly, the present invention also relates to a composition whichincludes a colorant and a functionalized molecular includant. Forillustrative purposes only, Examples 12 through 19, and 21 through 22disclose other methods of preparing and associating colorants andultraviolet radiation transorbers to cyclodextrins, wherein more thantwo molecules of the ultraviolet radiation transorber are covalentlycoupled to each molecule of the molecular includant.

The present invention also provides a method of making a functionalizedmolecular includant. The method of making a functionalized molecularincludant involves the steps of providing a derivatized ultravioletradiation transorber having a nucleophilic group, providing aderivatized molecular includant having more than two leaving groups permolecule, and reacting the derivatized ultraviolet radiation transorberwith the derivatized molecular includant under conditions sufficient toresult in the covalent coupling of an average of more than twoultraviolet radiation transorber molecules to each molecular includantmolecule. By way of example, the derivatized ultraviolet radiationtransorber may be 2-[p-(2-methyl-2-mercaptomethylpropionyl)phenoxy]ethyl1,3-dioxo-2-isoindolineacetate. As another example, the derivatizedultraviolet radiation transorber may be2-mercaptomethyl-2-methyl-4'-[2-[p-(3-oxobutyl)phenoxy]ethoxy]propiophenone.

In general, the derivatized ultraviolet radiation transorber and thederivatized molecular includant are selected to cause the covalentcoupling of the ultraviolet radiation transorber to the molecularincludant by means of a bimolecular nucleophilic substitution reaction.Consequently, the choice of the nucleophilic group and the leavinggroups and the preparation of the derivatized ultraviolet radiationtransorber and derivatized molecular includant, respectively, may bereadily accomplished by those having ordinary skill in the art withoutthe need for undue experimentation.

The nucleophilic group of the derivatized ultraviolet radiationtransorber may be any nucleophilic group capable of participating in abimolecular nucleophilic substitution reaction, provided, of course,that the reaction results in the covalent coupling of more than twomolecules of the ultraviolet radiation transorber to the molecularincludant. The nucleophilic group generally will be a Lewis base, i.e.,any group having an unshared pair of electrons. The group may be neutralor negatively charged. Examples of nucleophilic groups include, by wayof illustration only, aliphatic hydroxy, aromatic hydroxy, alkoxides,carboxy, carboxylate, amino, and mercapto.

Similarly, the leaving group of the derivatized molecular includant maybe any leaving group capable of participating in a bimolecularnucleophilic substitution reaction, again provided that the reactionresults in the covalent coupling of more than two molecules of theultraviolet radiation transorber to the molecular includant. Examples ofleaving groups include, also by way of illustration only,p-toluenesulfonates (tosylates), p-bromobenzenesulfonates (brosylates),p-nitrobenzenesulfonates (nosylates), methanesulfonates (mesylates),oxonium ions, alkyl perchlorates, ammonioalkane sulfonate esters(betylates), alkyl fluorosulfonates, trifluoromethanesulfonates(triflates), nonafluorobutanesulfonates (nonaflates), and2,2,2-trifluoroethanesulfonates (tresylates).

The reaction of the derivatized ultraviolet radiation transorber withthe derivatized molecular includant is carried out in solution. Thechoice of solvent depends upon the solubilities of the two derivatizedspecies. As a practical matter, a particularly useful solvent isN,N-dimethylformamide (DMF).

The reaction conditions, such as temperature, reaction time, and thelike generally are matters of choice based upon the natures of thenucleophilic and leaving groups. Elevated temperatures usually are notrequired. For example, the reaction temperature may be in a range offrom about 0° C. to around ambient temperature, i.e., to 20°-25° C.

The preparation of the functionalized molecular includant as describedabove generally is carried out in the absence of the colorant. However,the colorant may be associated with the derivatized molecular includantbefore reacting the derivatized ultraviolet radiation transorber withthe derivatized molecular includant, particularly if a degree ofsubstitution greater than about three is desired. When the degree ofsubstitution is about three, it is believed that the association of thecolorant with the functionalized molecular includant still may permitthe colorant to be at least partially included in a cavity of thefunctionalized molecular includant. At higher degrees of substitution,such as about six, steric hindrance may partially or completely preventthe colorant from being at least partially included in a cavity of thefunctionalized molecular includant. Consequently, the colorant may beassociated with the derivatized molecular includant which normally willexhibit little, if any, steric hindrance. In this instance, the colorantwill be at least partially included in a cavity of the derivatizedmolecular includant. The above-described bimolecular nucleophilicsubstitution reaction then may be carried out to give a coloredcomposition of the present invention in which the colorant is at leastpartially included in a cavity of the functionalized molecularincludant.

As stated above, the present invention provides compositions comprisinga colorant which, in the presence of a radiation transorber, is mutablewhen exposed to a specific wavelength of radiation, while at the sametime, provides light stability to the colorant with respect to sunlightand artificial light. Desirably, the mutated colorant will be stable,i.e., not appreciably adversely affected by radiation normallyencountered in the environment, such as natural or artificial light andheat. Thus, desirably, a colorant rendered colorless will remaincolorless indefinitely.

The dye, for example, may be an organic dye. Organic dye classesinclude, by way of illustration only, triarylmethyl dyes, such asMalachite Green Carbinol base{4-(dimethylamino)-α-[4-(dimethylamino)phenyl]α-phenylbenzene-methanol},Malachite Green Carbinol hydrochloride{N-4-[[4-(dimethylamino)phenyl]phenylmethylene]-2,5-cyclohexyldien-1-ylidene]-N-methyl-methanaminiumchloride or bis[p-(dimethylamino)phenyl]phenylmethylium chloride}, andMalachite Green oxalate{N-4-[[4(dimethylamino)phenyl]phenylmethylene]-2,5-cyclohexyldien-1-ylidene]-N-methylmethanaminiumchloride or bis[p-(dimethylamino)phenyl]phenylmethylium oxalate};monoazo dyes, such as Cyanine Black, Chrysoidine [Basic Orange 2;4-(phenylazo)-1,3-benzenediamine monohydrochloride], Victoria Pure BlueBO, Victoria Pure Blue B, basic fuschin and B-Naphthol Orange; thiazinedyes, such as Methylene Green, zinc chloride double salt[3,7-bis(dimethylamino)-6-nitrophenothiazin-5-ium chloride, zincchloride double salt]; oxazine dyes, such as Lumichrome(7,8-dimethylalloxazine); naphthalimide dyes, such as Lucifer Yellow CH{6-amino-2-[(hydrazinocarbonyl)amino]-2,3-dihydro-1,3-dioxo-1H-benz[de]isoquinoline-5,8-disulfonicacid dilithium salt}; azine dyes, such as Janus Green B{3-(diethylamino)-7-[[4-(dimethylamino)phenyl]azo]-5-phenylphenaziniumchloride}; cyanine dyes, such as Indocyanine Green {Cardio-Green or FoxGreen;2-[7-[1,3-dihydro-1,1-dimethyl-3-(4-sulfobutyl)-2H-benz[e]indol-2-ylidene]-1,3,5-heptatrienyl]-1,1-dimethyl-3-(4-sulfobutyl)-1H-benz[e]indoliumhydroxide inner salt sodium salt}; indigo dyes, such as Indigo {IndigoBlue or Vat Blue 1;2-(1,3-dihydro-3-oxo-2H-indol-2-ylidene)-1,2-dihydro-3H-indol-3-one};coumarin dyes, such as 7-hydroxy-4-methylcoumarin(4-methylumbelliferone); benzimidazole dyes, such as Hoechst 33258[bisbenzimide or2-(4-hydroxyphenyl)-5-(4-methyl-1-piperazinyl)-2,5-bi-1H-benzimidazoletrihydrochloride pentahydrate]; paraquinoidal dyes, such as Hematoxylin{Natural Black 1; 7,11b-dihydrobenz[b]indeno[1,2-d]pyran-3,4,6a,9,10(6H)-pentol}; fluorescein dyes, such as Fluoresceinamine(5-aminofluorescein); diazonium salt dyes, such as Diazo Red RC (AzoicDiazo No. 10 or Fast Red RC salt; 2-methoxy-5-chlorobenzenediazoniumchloride, zinc chloride double salt); azoic diazo dyes, such as FastBlue BB salt (Azoic Diazo No. 20; 4-benzoylamino-2,5-diethoxybenzenediazonium chloride, zinc chloride double salt); phenylenediamine dyes,such as Disperse Yellow 9[N-(2,4-dinitrophenyl)-1,4-phenylenediamine orSolvent Orange 53]; diazo dyes, such as Disperse Orange 13 [SolventOrange 52; 1-phenylazo-4-(4-hydroxyphenylazo)naphthalene]; anthraquinonedyes, such as Disperse Blue 3[Celliton Fast Blue FFR;1-methylamino-4-(2-hydroxyethylamino)-9,10-anthraquinone], Disperse Blue14 [Celliton Fast Blue B; 1,4-bis(methylamino)-9,10-anthraquinone], andAlizarin Blue Black B (Mordant Black 13); trisazo dyes, such as DirectBlue 71 {Benzo Light Blue FFL or Sirius Light Blue BRR;3-[(4-[(4-[(6-amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo]-6-sulfo-1-naphthalenyl)azo]-1-naphthalenyl)azo]-1,5-naphthalenedisulfonicacid tetrasodium salt}; xanthene dyes, such as 2,7-dichlorofluorescein;proflavine dyes, such as 3,6-diaminoacridine hemisulfate (Proflavine);sulfonaphthalein dyes, such as Cresol Red (o-cresolsulfonaphthalein);phthalocyanine dyes, such as Copper Phthalocyanine {Pigment Blue 15;(SP-4-1)-[29H,31H-phthalocyanato(2-)-N²⁹,N³⁰,N³¹,N³² ]copper};carotenoid dyes, such as trans-β-carotene (Food Orange 5); carminic aciddyes, such as Carmine, the aluminum or calcium-aluminum lake of carminicacid(7-a-D-glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-1-methyl-9,10-dioxo-2-anthracenecarbonylicacid); azure dyes, such as Azure A[3-amino-7-(dimethylamino)phenothiazin-5-ium chloride or7-(dimethylamino)-3-imino-3H-phenothiazine hydrochloride]; and acridinedyes, such as Acridine Orange [Basic Orange 14;3,8-bis(dimethylamino)acridine hydrochloride, zinc chloride doublesalt]and Acriflavine (Acriflavine neutral;3,6-diamino-10-methylacridinium chloride mixture with3,6-acridinediamine).

The present invention includes unique compounds, namely, radiationtransorbers, that are capable of absorbing narrow ultraviolet wavelengthradiation, while at the same time, imparting light-stability to acolorant with which the compounds are associated. The compounds aresynthesized by combining a wavelength-selective sensitizer and aphotoreactor. The photoreactors oftentimes do not efficiently absorbhigh energy radiation. When combined with the wavelength-selectivesensitizer, the resulting compound is a wavelength specific compoundthat efficiently absorbs a very narrow spectrum of radiation. Thewavelength-selective sensitizer may be covalently coupled to thephotoreactor.

By way of example, the wavelength-selective sensitizer may be selectedfrom the group consisting of phthaloylglycine and4-(4-oxyphenyl)-2-butanone. As another example, the photoreactor may beselected from the group consisting of1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methylpropan-1-one andcyclohexyl-phenyl ketone ester. Other photoreactors are listed by way ofexample, in the detailed description below regarding the improvedstabilized composition of the present invention. As a further example,the ultraviolet radiation transorber may be2-[p-2-methyllactoyl)phenoxy]ethyl 1,3-dioxo-2-isoin-dolineacetate. Asstill another example, the ultraviolet radiation transorber may be2-hydroxy-2-methyl-4'-2-[p-(3-oxobutyl)phenoxy]propiophenone.

Although the colorant and the ultraviolet radiation transorber have beendescribed as separate compounds, they can be part of the same molecule.For example, they can be covalently coupled to each other, eitherdirectly, or indirectly through a relatively small molecule, or spacer.Alternatively, the colorant and ultraviolet radiation transorber can becovalently coupled to a large molecule, such as an oligomer or apolymer. Further, the colorant and ultraviolet radiation transorber maybe associated with a large molecule by van der Waals forces, andhydrogen bonding, among other means. Other variations will be readilyapparent to those having ordinary skill in the art.

For example, in an embodiment of the composition of the presentinvention, the composition further comprises a molecular includant.Thus, the cavity in the molecular includant can be a tunnel through themolecular includant or a cave-like space or a dented-in space in themolecular includant. The cavity can be isolated or independent, orconnected to one or more other cavities.

The molecular includant can be inorganic or organic in nature. Incertain embodiments, the chemical structure of the molecular includantis adapted to form a molecular inclusion complex. Examples of molecularincludants are, by way of illustration only, clathrates or intercalates,zeolites, and cyclodextrins. Examples of molecular includants are, byway of illustration only, clathrates or intercalates, zeolites, andcyclodextrins. Examples of cyclodextrins include, but are not limitedto, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, hydroxypropylβ-cyclodextrin, hydroxyethyl β-cyclodextrin, sulfated β-cyclodextrin,hydroxyethyl α cyclodextrin, carboxymethyle α cyclodextrin,carboxymethyl β cyclodextrin, carboxymethyl γ cyclodextrin, octylsuccinated α cyclodextrin, octyl succinated β cyclodextrin, octylsuccinated γ cyclodextrin and sulfated β and γ-cyclodextrin (AmericanMaize-Products Company, Hammond, Ind.).

The desired molecular includant is α-cyclodextrin. More particularly, insome embodiments, the molecular includant is an α-cyclodextrin. In otherembodiments, the molecular includant is a beta-cyclodextrin. Althoughnot wanting to be bound by the following theory, it is believed that thecloser the transorber molecule is to the mumble colorant on themolecular includant, the more efficient the interaction with thecolorant to effect mutation of the colorant. Thus, the molecularincludant with functional groups that can react with and bind thetransorber molecule and that are close to the binding site of themutable colorant are the more desirable molecular includants.

In some embodiments, the colorant and the ultraviolet radiationtransorber are associated with the molecular includant. The term"associated", in its broadest sense, means that the colorant and theultraviolet radiation transorber are at least in close proximity to themolecular includant. For example, the colorant and/or the ultravioletradiation transorber can be maintained in close proximity to themolecular includant by hydrogen bonding, van der Waals forces, or thelike. Alternatively, either or both of the colorant and the ultravioletradiation transorber can be covalently bonded to the molecularincludant. In certain embodiments, the colorant will be associated withthe molecular includant by means of hydrogen bonding and/or van derWaals forces or the like, while the ultraviolet radiation transorber iscovalently bonded to the molecular includant. In other embodiments, thecolorant is at least partially included within the cavity of themolecular includant, and the ultraviolet radiation transorber is locatedoutside of the cavity of the molecular includant.

In one embodiment wherein the colorant and the ultraviolet radiationtransorber are associated with the molecular includant, the colorant iscrystal violet, the ultraviolet radiation transorber is a dehydratedphthaloylglycine-2959, and the molecular includant is beta-cyclodextrin.In yet another embodiment wherein the colorant and the ultravioletradiation transorber are associated with the molecular includant, thecolorant is crystal violet, the ultraviolet radiation transorber is4(4-hydroxyphenyl) butan-2-one-2959 (chloro substituted), and themolecular includant is beta-cyclodextrin.

In another embodiment wherein the colorant and the ultraviolet radiationtransorber are associated with the molecular includant, the colorant ismalachite green, the ultraviolet radiation transorber is IRGACURE 184,and the molecular includant is beta-cyclodextrin as shown in FIG. 1. Instill another embodiment wherein the colorant and the ultravioletradiation transorber are associated with the molecular includant, thecolorant is Victoria Pure Blue BO, the ultraviolet radiation transorberis IRGACURE 184, and the molecular includant is beta-cyclodextrin asshown in FIG. 2.

The present invention also relates to a method of mutating the colorantin the composition of the present invention. Briefly described, themethod comprises irradiating a composition containing a mutable colorantand a radiation transorber with radiation at a dosage level sufficientto mutate the colorant. As stated above, in one embodiment thecomposition further includes a molecular includant. In anotherembodiment, the composition is applied to a substrate before beingirradiated with ultraviolet radiation.

The radiation to which the photoreactor composition is exposed may havea wavelength of from about 4 to about 1000 nanometers. Thus, theradiation may be ultraviolet radiation, including near ultraviolet andfar or vacuum ultraviolet radiation, visible radiation, and nearinfrared radiation. The radiation may have a wavelength of from about100 to about 900 nanometers.

Desirably, the composition of the present invention is irradiated withultraviolet radiation having a wavelength of from about 4 to about 400nanometers. It is more desirable that the radiation has a wavelength ofbetween about 100 to 375 nanometers. Especially desirable radiation isincoherent, pulsed ultraviolet radiation produced by a dielectricbarrier discharge lamp. Even more desirably, the dielectric barrierdischarge lamp produces radiation having a narrow bandwidth.

The amount or dosage level of ultraviolet radiation that the colorant ofthe present invention is exposed to will generally be that amount whichis necessary to mutate the colorant. The amount of ultraviolet radiationnecessary to mutate the colorant can be determined by one of ordinaryskill in the art using routine experimentation. Power density is themeasure of the amount of radiated electromagnetic power traversing aunit area and is usually expressed in watts per centimeter squared(W/cm²). The power density level range is between approximately 5 mW/cm²and 15 mW/cm², more particularly 8 to 10 mW/cm². The dosage level, inturn, typically is a function of the time of exposure and the intensityor flux of the radiation source which irradiates the coloredcomposition. The latter is affected by the distance of the compositionfrom the source and, depending upon the wavelength range of theultraviolet radiation, can be affected by the atmosphere between theradiation source and the composition. Accordingly, in some instances itmay be appropriate to expose the composition to the radiation in acontrolled atmosphere or in a vacuum, although in general neitherapproach is desired.

With regard to the mutation properties of the present invention,photochemical processes involve the absorption of light quanta, orphotons, by a molecule, e.g., the ultraviolet radiation transorber, toproduce a highly reactive electronically excited state. However, thephoton energy, which is proportional to the wavelength of the radiation,cannot be absorbed by the molecule unless it matches the energydifference between the unexcited, or original, state and an excitedstate. Consequently, while the wavelength range of the ultravioletradiation to which the colored composition is exposed is not directly ofconcern, at least a portion of the radiation must have wavelengths whichwill provide the necessary energy to raise the ultraviolet radiationtransorber to an energy level which is capable of interacting with thecolorant.

It follows, then, that the absorption maximum of the ultravioletradiation transorber ideally will be matched with the wavelength rangeof the ultraviolet radiation to increase the efficiency of the mutationof the colorant. Such efficiency also will be increased if thewavelength range of the ultraviolet radiation is relatively narrow, withthe maximum of the ultraviolet radiation transorber coming within suchrange. For these reasons, especially suitable ultraviolet radiation hasa wavelength of from about 100 to about 375 nanometers. Ultravioletradiation within this range desirably may be incoherent, pulsedultraviolet radiation from a dielectric barrier discharge excimer lamp.

The term "incoherent, pulsed ultraviolet radiation" has reference to theradiation produced by a dielectric barrier discharge excimer lamp(referred to hereinafter as "excimer lamp"). Such a lamp is described,for example, by U. Kogelschatz, "Silent discharges for the generation ofultraviolet and vacuum ultraviolet excimer radiation," Pure & Appl.Chem., 62, No. 9, pp. 1667-1674 (1990); and E. Eliasson and U.Kogelschatz, "UV Excimer Radiation from Dielectric-Barrier Discharges,"Appl. Phys. B, 46, pp. 299-303 (1988). Excimer lamps were developedoriginally by ABB Infocom Ltd., Lenzburg, Switzerland. The excimer lamptechnology since has been acquired by Haraus Noblelight AG, Hanau,Germany.

The excimer lamp emits incoherent, pulsed ultraviolet radiation. Suchradiation has a relatively narrow bandwidth, i.e., the half width is ofthe order of approximately 5 to 100 nanometers. Desirably, the radiationwill have a half width of the order of approximately 5 to 50 nanometers,and more desirably will have a half width of the order of 5 to 25nanometers. Most desirably, the half width will be of the order ofapproximately 5 to 15 nanometers. This emitted radiation is incoherentand pulsed, the frequency of the pulses being dependent upon thefrequency of the alternating current power supply which typically is inthe range of from about 20 to about 300 kHz. An excimer lamp typicallyis identified or referred to by the wavelength at which the maximumintensity of the radiation occurs, which convention is followedthroughout this specification. Thus, in comparison with most othercommercially useful sources of ultraviolet radiation which typicallyemit over the entire ultraviolet spectrum and even into the visibleregion, excimer lamp radiation is substantially monochromatic.

Excimers are unstable molecular complexes which occur only under extremeconditions, such as those temporarily existing in special types of gasdischarge. Typical examples are the molecular bonds between two raregaseous atoms or between a rare gas atom and a halogen atom. Excimercomplexes dissociate within less than a microsecond and, while they aredissociating, release their binding energy in the form of ultravioletradiation. Known excimers, in general, emit in the range of from about125 to about 360 nanometers, depending upon the excimer gas mixture.

In addition to excimer lamps, it is specifically contemplated that thecolored composition of the present invention can be mutated with thelight from a laser, particularly, an excimer laser. An excimer laser isa laser containing a noble gas, such as helium or neon, or halides ofthe noble gases, as its active medium. Excimer lasers are pulsed andproduce high peak powers in the ultraviolet spectrum.

For example, in one embodiment, the colorant of the present invention ismutated by exposure to 222 nanometer excimer lamps. More particularly,the colorant crystal violet is mutated by exposure to 222 nanometerlamps. Even more particularly, the colorant crystal violet is mutated byexposure to 222 nanometer excimer lamps located approximately 5 to 6centimeters from the colorant, wherein the lamps are arranged in fourparallel columns approximately 30 centimeters long. It is to beunderstood that the arrangement of the lamps is not critical to thisaspect of the invention. Accordingly, one or more lamps may be arrangedin any configuration and at any distance which results in the colorantmutating upon exposure to the lamp's ultraviolet radiation. One ofordinary skill in the art would be able to determine by routineexperimentation which configurations and which distances areappropriate. Also, it is to be understood that different excimer lampsare to be used with different ultraviolet radiation transorbers. Theexcimer lamp used to mutate a colorant associated with an ultravioletradiation transorber should produce ultraviolet radiation of awavelength that is absorbed by the ultraviolet radiation transorber.

In some embodiments, the molar ratio of ultraviolet radiation transorberto colorant generally will be equal to or greater than about 0.5. As ageneral rule, the more efficient the ultraviolet radiation transorber isin absorbing the ultraviolet radiation and interacting with, i.e.,transferring absorbed energy to, the colorant to effect irreversiblemutation of the colorant, the lower such ratio can be. Current theoriesof molecular photo chemistry suggest that the lower limit to such ratiois 0.5, based on the generation of two free radicals per photon. As apractical matter, however, ratios higher than 1 are likely to berequired, perhaps as high as about 10. However, the present invention isnot bound by any specific molar ratio range. The important feature isthat the transorber is present in an amount sufficient to effectmutation of the colorant.

While the mechanism of the interaction of the ultraviolet radiationtransorber with the colorant is not totally understood, it is believedthat it may interact with the colorant in a variety of ways. Forexample, the ultraviolet radiation transorber, upon absorbingultraviolet radiation, may be converted to one or more free radicalswhich interact with the colorant. Such free radical-generating compoundstypically are hindered ketones, some examples of which include, but arenot limited to: benzildimethyl ketal (available commercially as IRGACURE651, Ciba-Geigy Corporation, Hawthorne, N.Y.); 1-hydroxycyclohexylphenyl ketone (IRGACURE 500);2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one](IRGACURE907); 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one(IRGACURE 369); and 1-hydroxycyclohexyl phenyl ketone (IRGACURE 184).

Alternatively, the ultraviolet radiation may initiate an electrontransfer or reduction-oxidation reaction between the ultravioletradiation transorber and the colorant. In this case, the ultravioletradiation transorber may be, but is not limited to, Michler's ketone(p-dimethylaminophenyl ketone) or benzyl trimethyl stannate. Or, acationic mechanism may be involved, in which case the ultravioletradiation transorber can be, for example,bis[4-(diphenylsulphonio)phenyl)]sulfide bis-(hexafluorophosphate)(Degacure KI85, Ciba-Geigy Corporation, Hawthorne, N.Y.); CyracureUVI-6990 (Ciba-Geigy Corporation), which is a mixture ofbis[4-(diphenylsulphonio)phenyl]sulfide bis(hexafluorophosphate) withrelated monosulphonium hexafluorophosphate salts; andn5-2,4-(cyclopentadienyl)[1,2,3,4,5,6-n-(methylethyl)benzene]-iron(II)hexafluorophosphate (IRGACURE 261).

With regard to the light stabilizing activity of the present invention,it has been determined that in some embodiments it is necessary tomodify a conventional photoreactor to produce the improved light stablecomposition of the present invention. The simplest form of the improvedlight stable composition of the present invention includes a colorantadmixed with a photoreactor modified as described below. The modifiedphotoreactor may or may not be combined with a wavelength-selectivesensitizer. Many conventional photoreactor molecules have a functionalgroup that is alpha to a carbonyl group. The functional group includes,but is not limited to, hydroxyl groups, ether groups, ketone groups, andphenyl groups.

For example, a preferred radiation transorber that can be used in thepresent invention is designated phthaloylglycine-2959 and is representedin the following formula: ##STR1##

The photoreactor portion of the ultraviolet radiation transorber has ahydroxyl group (shaded portion) alpha to the carbonyl carbon. The abovemolecule does not light-stabilize a colorant. However, the hydroxylgroup can be removed by dehydration (see Example 4 and 5) yielding thecompound represented by the following formula: ##STR2## This dehydratedphthaloylglycine-2959 is capable of light-stabilizing a colorant. Thus,it is believed that removal of the functional group alpha to thecarbonyl carbon on any photoreactor molecule will impart thelight-stabilizing capability to the molecule. While the dehydratedultraviolet radiation transorber can impart light-stability to acolorant simply by mixing the molecule with the colorant, it has beenfound that the molecule is much more efficient at stabilizing colorantswhen it is attached to an includant, such as cyclodextrin, as describedherein.

It is to be understood that stabilization of a colorant can beaccomplished according to the present invention by utilizing only themodified photoreactor. In other words, a modified photoreactor without awavelength selective sensitizer may be used to stabilize a colorant. Anexample of a photoreactor that is modified according to the presentinvention is DARCUR 2959. The unmodified DARCUR 2959 and the dehydratedDARCUR 2959 are represented by the following formulas: ##STR3## Otherphotoreactors can be modified according to the present invention toprovide stabilizers for dyes. These photoreactors include, but are notlimited to: 1-Hydroxy-cyclohexyl-phenyl ketone ("HCPK") (IRGACURE 184,Ciba-Geigy); α,α-dimethoxy-α-hydroxy acetophenone (DAROCUR 1173, Merck);1-(4-Isopropylphenyl)-2-hydroxy-2-methyl-propan-1-one (DAROCUR 1116,Merck); 1-[4-(2-Hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-propan-1-one(DAROCUR 2959, Merck);Poly[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one](ESACUREKIP, Fratelli Lamberti); Benzoin (2-Hydroxy-1,2-diphenylethanone)(ESACURE BO, Fratelli Lamberti); Benzoin ethyl ether(2-Ethoxy-1,2-diphenylethanone) (DAITOCURE EE, Siber Hegner); Benzoinisopropyl ether (2-Isopropoxy-1,2-diphenylethanone) (VICURE 30,Stauffer); Benzoin n-butyl ether (2-Butoxy-1,2-diphenylethanone)(ESACURE EB1, Fratelli Lamberti); mixture of benzoin butyl ethers(TRIGONAL 14, Akzo); Benzoin iso-butyl ether(2-Isobutoxy-1,2-diphenylethanone) (VICURE 10, Stauffer); blend ofbenzoin n-butyl ether and benzoin isobutyl ether (ESACURE EB3, ESACUREEB4, Fratelli Lamberti); Benzildimethyl ketal(2,2-Dimethoxy-1,2-diphenylethanone) ("BDK") (IRGACURE 651, Ciba-Geigy);2,2-Diethoxy-1,2-diphenylethanone (UVATONE 8302, Upjohn); α,α-Diethoxyacetophenone (2,2- Diethoxy-1-phenyl-ethanone) "DEAP",Upjohn), (DEAP, Rahn); and α,α-Di-(n-butoxy)-acetophenone(2,2-Dibutoxyl-1-phenyl-ethanone) (UVATONE 8301, Upjohn).

It is known to those of ordinary skill in the art that the dehydrationby conventional means of the tertiary alcohols that are alpha to thecarbonyl groups is difficult. One conventional reaction that can be usedto dehydrate the phthaloylglycine-2959 is by reacting thephthaloylglycine-2959 in anhydrous benzene in the presence ofp-toluenesulfonic acid. After refluxing the mixture, the final productis isolated. However, the yield of the desired dehydrated alcohol isonly about 15 to 20% by this method.

To increase the yield of the desired dehydrated phthaloylglycine-2959, anew reaction was invented. The reaction is summarized as follows:##STR4##

It is to be understood that the groups on the carbon alpha to thecarbonyl group can be groups other than methyl groups such as aryl orheterocyclic groups. The only limitation on these groups are stericlimitations. Desirably, the metal salt used in the Nohr-MacDonaldelimination reaction is ZnCl₂. It is to be understood that othertransition metal salts can be used in performing the Nohr-MacDonaldelimination reaction but ZnCl₂ is the preferred metal salt. The amountof metal salt used in the Nohr-MacDonald elimination reaction isdesirably approximately equimolar to the tertiary alcohol compound, suchas the photoreactor. The concentration of tertiary alcohol in thereaction solution is between approximately 4% and 50% w/v.

Thus, the stabilizing composition produced by the process of dehydratinga tertiary alcohol that is alpha to a carbonyl group on a photoreactoris represented in the following general formula: ##STR5##

wherein R₁ is hydrogen, an alkane, an alkene, or an aryl group;

wherein R₂ is hydrogen, an alkane, an alkene, or an aryl group;

wherein R₃ is hydrogen, an alkane, an alkene, or an aryl group; and

wherein R₄ is an aryl, or substituted aryl group.

Another requirement of the reaction is that it be run in a non-aqueous,non-polar solvent. The preferred solvents for running the Nohr-MacDonaldelimination reaction are aromatic hydrocarbons including, but notlimited to, xylene, benzene, toluene, cumene, mesitylene, p-cymene,butylbenzene, styrene, and divinylbenzene. It is to be understood thatother substituted aromatic hydrocarbons can be used as solvents in thepresent invention. p-Xylene is the preferred aromatic hydrocarbonsolvent, but other isomers of xylene can be used in performing theNohr-MacDonald elimination reaction.

An important requirement in performing the Nohr-MacDonald eliminationreaction is that the reaction be run at a relatively high temperature.The reaction is desirably performed at a temperature of betweenapproximately 80° C. and 150° C. A suitable temperature for dehydratingphthaloylglycine-2959 is approximately 124° C. The time the reactionruns is not critical. The reaction should be run between approximately30 minutes to 4 hours. However, depending upon the reactants and thesolvent used, the timing may vary to achieve the desired yield ofproduct.

It is to be understood that the dehydrated phthaloylglycine -2959 can beattached to the molecular includant in a variety of ways. In oneembodiment, the dehydrated phthaloylglycine-2959 is covalently attachedto the cyclodextrin as represented in the following formula: ##STR6##

In another embodiment, as shown below, only the modified DARCUR 2959without the phthaloyl glycine attached is reacted with the cyclodextrinto yield the following compound. This compound is capable of stabilizinga dye that is associated with the molecular includant and is representedby the following formula: ##STR7##

It is to be understood that photoreactors other than DARCUR 2959 can beused in the present invention.

In yet another embodiment, the dehydrated phthaloylglycine-2959 can beattached to the molecular includant via the opposite end of themolecule. One example of this embodiment is represented in the followingformula: ##STR8##

As a practical matter, the colorant, ultraviolet radiation transorber,modified photoreactor, and molecular includant are likely to be solidsdepending upon the constituents used to prepare the molecules. However,any or all of such materials can be a liquid. The colored compositioncan be a liquid either because one or more of its components is aliquid, or, when the molecular includant is organic in nature, a solventis employed. Suitable solvents include, but are not limited to, amides,such as N,N-dimethylformamide; sulfoxides, such as dimethylsulfoxide;ketones, such as acetone, methyl ethyl ketone, and methyl butyl ketone;aliphatic and aromatic hydrocarbons, such as hexane, octane, benzene,toluene, and the xylenes; esters, such as ethyl acetate; water; and thelike. When the molecular includant is a cyclodextrin, particularlysuitable solvents are the amides and sulfoxides.

In an embodiment where the composition of the present invention is asolid, the effectiveness of the above compounds on the colorant isimproved when the colorant and the selected compounds are in intimatecontact. To this end, the thorough blending of the components, alongwith other components which may be present, is desirable. Such blendinggenerally is accomplished by any of the means known to those havingordinary skill in the art. When the colored composition includes apolymer, blending is facilitated if the colorant and the ultravioletradiation transorber are at least partly soluble in softened or moltenpolymer. In such case, the composition is readily prepared in, forexample, a two-roll mill. Alternatively, the composition of the presentinvention can be a liquid because one or more of its components is aliquid.

For some applications, the composition of the present inventiontypically will be utilized in particulate form. In other applications,the particles of the composition should be very small. Methods offorming such particles are well known to those having ordinary skill inthe art.

The colored composition of the present invention can be utilized on orin any substrate. If one desires to mutate the colored composition thatis present in a substrate, however, the substrate should besubstantially transparent to the ultraviolet radiation which is employedto mutate the colorant. That is, the ultraviolet radiation will notsignificantly interact with or be absorbed by the substrate. As apractical matter, the composition typically will be placed on asubstrate, with the most common substrate being paper. Other substrates,including, but not limited to, woven and nonwoven webs or fabrics,films, and the like, can be used, however.

The colored composition optionally may also contain a carrier, thenature of which is well known to those having ordinary skill in the art.For many applications, the carrier will be a polymer, typically athermosetting or thermoplastic polymer, with the latter being the morecommon.

Further examples of thermoplastic polymers include, but are not limitedto: end-capped polyacetals, such as poly(oxymethylene) orpolyformaldehyde, poly(trichloroacetaldehyde), poly(n-valeraldehyde),poly(acetaldehyde), poly(propionaldehyde), and the like; acrylicpolymers, such as polyacrylamide, poly(acrylic acid), poly(methacrylicacid), poly(ethyl acrylate), poly(methyl methacrylate), and the like;fluorocarbon polymers, such as poly(tetrafluoroethylene), perfluorinatedethylenepropylene copolymers, ethylenetetrafluoroethylene copolymers,poly(chlorotrifluoroethylene), ethylene- chlorotrifluoroethylenecopolymers, poly(vinylidene fluoride), poly(vinyl fluoride), and thelike; epoxy resins, such as the condensation products of epichlorohydrinand bisphenol A; polyamides, such as poly(6-aminocaproic acid) orpoly(E-caprolactam), poly(hexamethylene adipamide), poly(hexamethylenesebacamide), poly(11-aminoundecanoic acid), and the like; polyaramides,such as poly(imino-1,3-phenyleneiminoisophthaloyl) or poly(m-phenyleneisophthalamide), and the like; parylenes, such as poly-p-xylylene,poly(chloro-p-xylene), and the like; polyaryl ethers, such aspoly(oxy-2,6-dimethyl-1,4-phenylene) or poly(p-phenylene oxide), and thelike; polyaryl sulfones, such aspoly(oxy-1,4-phenylenesulfonyl-1,4-phenyleneoxy-1,4-phenylene-isopropylidene-1,4-phenylene),poly(sulfonyl-1,4-phenyleneoxy-1,4-phenylenesulfonyl-4,4-biphenylene),and the like; polycarbonates, such as poly(bisphenol A) orpoly(carbonyldioxy-1,4-phenyleneisopropylidene-1,4-phenylene), and thelike; polyesters, such as poly(ethylene terephthalate),poly(tetramethylene terephthalate), poly(cyclohexylene-1,4-dimethyleneterephthalate) orpoly(oxymethylene-1,4-cyclohexylenemethyleneoxyterephthaloyl), and thelike; polyaryl sulfides, such as poly(p-phenylene sulfide) orpoly(thio-1,4-phenylene), and the like; polyimides, such aspoly(pyromellitimido-1,4-phenylene), and the like; polyolefins, such aspolyethylene, polypropylene, poly(1-butene), poly(2-butene),poly(1-pentene), poly(2-pentene), poly(3-methyl-1-pentene),poly(4-methyl-1-pentene), 1,2-poly-1,3-butadiene,1,4-poly-1,3-butadiene, polyisoprene, polychloroprene,polyacrylonitrile, poly(vinyl acetate), poly(vinylidene chloride),polystyrene, and the like; and copolymers of the foregoing, such asacrylonitrile-butadienestyrene (ABS) copolymers,styrene-n-butylmethacrylate copolymers, ethylene-vinyl acetatecopolymers, and the like.

Some of the more commonly used thermoplastic polymers includestyrene-n-butyl methacrylate copolymers, polystyrene, styrene-n-butylacrylate copolymers, styrene-butadiene copolymers, polycarbonates,poly(methyl methacrylate), poly(vinylidene fluoride), polyamides(nylon-12), polyethylene, polypropylene, ethylene-vinyl acetatecopolymers, and epoxy resins.

Examples of thermosetting polymers include, but are not limited to,alkyd resins, such as phthalic anhydride-glycerol resins, maleicacid-glycerol resins, adipic acid-glycerol resins, and phthalicanhydride-pentaerythritol resins; allylic resins, in which such monomersas diallyl phthalate, diallyl isophthalate diallyl maleate, and diallylchlorendate serve as nonvolatile cross-linking agents in polyestercompounds; amino resins, such as aniline-formaldehyde resins, ethyleneurea-formaldehyde resins, dicyandiamide-formaldehyde resins,melamine-formaldehyde resins, sulfonamide-formaldehyde resins, andurea-formaldehyde resins; epoxy resins, such as cross-linkedepichlorohydrin-bisphenol A resins; phenolic resins, such asphenol-formaldehyde resins, including Novolacs and resols; andthermosetting polyesters, silicones, and urethanes.

In addition to the colorant, and ultraviolet radiation transorber orfunctionalized molecular includant, modified photoreactor, and optionalcarrier, the colored composition of the present invention also cancontain additional components, depending upon the application for whichit is intended. Examples of such additional components include, but arenot limited to, charge carriers, stabilizers against thermal oxidation,viscoelastic properties modifiers, cross-linking agents, plasticizers,charge control additives such as a quaternary ammonium salt; flowcontrol additives such as hydrophobic silica, zinc stearate, calciumstearate, lithium stearate, polyvinylstearate, and polyethylene powders;and fillers such as calcium carbonate, clay and talc, among otheradditives used by those having ordinary skill in the art. Charge cardersare well known to those having ordinary skill in the art and typicallyare polymer-coated metal particles. The identifies and amounts of suchadditional components in the colored composition are well known to oneof ordinary skill in the art.

The present invention comprises a substrate, such as an optical disk,having a layer of the colored composition disposed thereon to form arecording layer. Briefly described, the method of recording informationon the recording layer comprises selectively irradiating regions of therecording layer comprising a composition containing a mutable colorantand a radiation transorber, particularly an ultraviolet radiationtransorber, with radiation, particularly ultraviolet radiation, at adosage level sufficient to mutate the colorant. As stated above, in oneembodiment the composition which forms the recording layer furtherincludes a molecular includant.

As stated above, the amount or dosage level of radiation that thecolorant of the present invention is exposed to will generally be thatamount which is necessary to mutate the colorant. The amount ofradiation necessary to mutate the colorant can be determined by one ofordinary skill in the art using routine experimentation. Power densityis the measure of the amount of radiated electromagnetic powertraversing a unit area and is usually expressed in watts per centimetersquared (W/cm²). The power density level range is between approximately5 mW/cm² and 15 mW/cm², more particularly 8 to 10 mW/cm².

The colored composition of the present invention can be utilized in arecording medium, such as on the substrate 12 of the optical disk 10shown in FIG. 7, to thereby form a recording layer, such as therecording layer 14 on one side of the optical disk. It is preferred thatthe colored composition be combined with a polymer, such as athermoforming or thermosetting plastic polymer, before it is applied tothe substrate 12. The polymer provides a matrix within which to containthe colored composition, to bind the colored composition to therecording medium substrate 12 and to protect the colored compositionfrom damage, such as by wear, abrasion, dirt and the like. The polymercontaining the colored composition can be applied to the substrate 12 byconventional techniques, such as spin coating, roll coating, sprayingand the like, in order to form a relatively thin layer on the surface ofthe substrate. This thin layer of colored composition and polymer formsthe recording layer 14 of the optical disk 10. The techniques forforming a polymer recording layer on a recording medium substrate arewell known to those skilled in the art and can be utilized in thepresent invention.

If the composition is combined with a polymer, the polymer should besubstantially transparent to the mutating ultraviolet radiation which isemployed to mutate the colorant. That is, the ultraviolet radiationshould not significantly interact with or be absorbed by the polymer.Suitable polymers for use when the mutating radiation is ultravioletlight include, but are not limited to, those polymers listed above.

Alternately, the colored composition can be incorporated with thematerial from which the recording medium substrate 12 is formed, againprovided that the material is substantially transparent to the mutatingradiation (FIG. 9). Therefore, the colored composition can be combinedwith a suitable polymer and then molded or otherwise formed into therecording medium, such as a disk, either plastic or metal, a film, atape or the like. It is particularly preferred that the coloredcomposition and polymer be formed into a plastic disk, such as anoptical disk; especially a compact disc. The techniques for formingpolymers into disks, films, tapes or the like, are well known to thoseskilled in the art and can be utilized in the present invention.

This alternate embodiment is illustrated in FIG. 9. Instead of having arecording layer formed on one surface of the recording medium substrate12, the substrate itself becomes the recording layer. By eliminating theneed for forming a thin layer on the surface of the substrate, a complexmanufacturing task can be eliminated, thereby making the recordingmedium easier to produce.

The optical disk 10 (FIG. 7) can be "recorded" with digital information,such as music, video, computer data, computer software, etc., byselectively exposing the recording layer 14 to mutating light,particularly ultraviolet light. The optical disk 10 is placed in asuitable optical disk drive (not shown) so that the disk is rotatablydriven. Referring now to FIG. 8, positioned above the surface of thedisk 10 which includes the recording layer 14 is an excimer laser 16which emits controlled pulses of ultraviolet light 18 of a wavelengthsuitable to mutate the colorant in the recording layer. When theultraviolet light 18 strikes the recording layer, it causes the colorantto mutate only in that area which is irradiated. Since the disk 10 isrotated and since the ultraviolet light 18 is pulsed, the portion of therecording layer 14 which is exposed to the radiation is a small arc 20.This small arcuate area 20 changes color from that of its surroundingarea 22. The colorant in the colored composition is selected so that thecolor change produces the maximum contrast between the area of mutatedcolor and the area of nonmutated color. The excimer laser 16 iscontrolled by a computer (not shown) so that the pulses of light emittedby the laser correspond to encoded information which is to be recordedon the disk. The series of pulses of light from the laser 16 produce aseries of mutated arcuate areas formed in a track around the disk 10(FIG. 10). The excimer laser 16 is radially movable with respect to thedisk, as shown by the arrow "A," so that multiple tracks can be recordedon the disk. Each area of mutated colorant corresponds to one portion ofa binary signal. For example, as shown in FIG. 10, the longer arcualtearcs 20a correspond to the binary digit "1" and the shorter arcuate arcs20b correspond to the binary digit "0.". In this manner, a series ofon's and off's, pluses and minuses, yeses and nos and the like, can berecorded on the recording layer 14. This binary information correspondsto encoded information in a digitally encoded format.

Alternately, for mass production of optical disk in accordance with thepresent invention, the optical disk 10 (FIG. 11) can be "recorded" withdigital information by selectively exposing the recording layer 14 toultraviolet light by placing a mask 24 over the recording layer andexposing the mask and underlying recording layer to ultraviolet fight 26from an excimer lamp 28. The mask 24 includes portions 30 which aretransparent to ultraviolet radiation and portions 32 which are opaque toultraviolet radiation. Typically, the mask 24 will be made byphotographic processes, or other similar processes, well known to thoseskilled in the art. Furthermore, the transparent portions 30 of the mask24 correspond to the arcuate portions 20 on the disc 10. When theultraviolet light 26 irradiates the mask 24, the ultraviolet lightpasses through the mask at the transparent portions 30 therebyselectively exposing the recording layer 14 to ultraviolet radiation atthe portions 20, thereby mutating the colorant at those locations. Themask 24 blocks or absorbs the ultraviolet radiation at locations otherthan the transparent portions 30 so that the areas surrounding theportions 20 remain unmutated. When the mask 24 is removed from the disc10, the recording layer 14 will in effect contain a photographic imageof the pattern of transparent portions of the mask. Although therecording process utilizing the mask is different from the processutilizing an excimer laser, the resulting disc 10 is identical in allessential aspects.

Referring now to FIG. 9, it is to be understood that the above methodsof producing and recording optical disks in accordance with the presentinvention also apply towards producing and recording optical disks wherethe substrate itself is the recording layer.

Referring again to FIG. 8, the binary digital information contained inthe recording layer 14 can be "read" from the disc 10 by illuminatingthe recording track with nonmutating radiation, such as visible light 34from a conventional red laser 36. Since the light from the laser 36 isof a wavelength to which the colorant in the recording layer is stable,the color of the colorant, whether already mutated or not, will beunchanged by the laser light 34. Since the mutated arcuate portions,such as 20, of the recording layer 14 have a different color, and,therefore, a different reflectance than the unmutated portions, thelight which is reflected from the recording layer 14 varies in intensitycorresponding to the pattern of mutated arcuate portions 20 on the disc10. The varying intensity of the reflected light 38 is detected by aphotodetector 40 which produces and electrical signal corresponding tothe varying intensity of the reflected light. The electrical signal fromthe photodetector 40 is sent to a computer where it is digitized storedor otherwise processed for its intended use.

Referring now to FIG. 9, it is to be understood that the above method ofreading optical disks in accordance with the present invention alsoapply towards reading optical disks where the substrate itself is therecording layer. Accordingly, the same methods of recording and readingoptical disks may be used whether the mutable colorant of the presentinvention is present as a layer 14 on the substrate 12 (FIG. 8), orwhether the mutable colorant is in the substrate 12 (FIG. 9).

It will be appreciated that since the colorant in the recording layer iscolor-stable with respect to sunlight and artificial light, light fromthose sources, such as at 42, will not mutate the colorant, and,thereby, does not cause fading of the colorant. This results in arelatively permanent recording medium which is stable with respect tomost conventional environmental conditions.

The present invention is further described by the examples which follow.Such examples, however, are not to be construed as limiting in any wayeither the spirit or scope of the present invention. In the examples,all parts are parts by weight unless stated otherwise.

EXAMPLE 1

This example describes the preparation of a β-cyclodextrin molecularincludant having (1) an ultraviolet radiation transorber covalentlybonded to the cyclodextrin outside of the cavity of the cyclodextrin,and (2) a colorant associated with the cyclodextrin by means of hydrogenbonds and/or van der Waals forces.

A. Friedel-Crafts Acylation of Transorber

A 250-ml, three-necked, round-bottomed reaction flask was fitted with acondenser and a pressure-equalizing addition funnel equipped with anitrogen inlet tube. A magnetic stirring bar was placed in the flask.While being flushed with nitrogen, the flask was charged with 10 g (0.05mole) of 1-hydroxycyclohexyl phenyl ketone (IRGACURE 184, Ciba-GeigyCorporation, Hawthorne, N.Y.), 100 ml of anhydrous tetrahydofuran(Aldrich Chemical Company, Inc., Milwaukee, Wis.), and 5 g (0.05 mole)of succinic anhydride (Aldrich Chemical Co., Milwaukee, Wis.). To thecontinuously stirred contents of the flask then was added 6.7 g ofanhydrous aluminum chloride (Aldrich Chemical Co., Milwaukee, Wis.). Theresulting reaction mixture was maintained at about 0° C. in an ice bathfor about one hour, after which the mixture was allowed to warm toambient temperature for two hours. The reaction mixture then was pouredinto a mixture of 500 ml of ice water and 100 ml of diethyl ether. Theether layer was removed after the addition of a small amount of sodiumchloride to the aqueous phase to aid phase separation. The ether layerwas dried over anhydrous magnesium sulfate. The ether was removed underreduced pressure, leaving 12.7 g (87 percent) of a white crystallinepowder. The material was shown to be 1-hydroxycyclohexyl4-(2-carboxyethyl)carbonylphenyl ketone by nuclear magnetic resonanceanalysis.

B. Preparation of AcyIated Transorber Acid Chloride

A 250-ml round-bottomed flask fitted with a condenser was charged with12.0 g of 1-hydroxycyclohexyl 4-(2-carboxyethyl)carbonylphenyl ketone(0.04 mole), 5.95 g (0.05 mole) of thionyl chloride (Aldrich ChemicalCo., Milwaukee, Wis.), and 50 ml of diethyl ether. The resultingreaction mixture was stirred at 30° C. for 30 minutes, after which timethe solvent was removed under reduced pressure. The residue, a whitesolid, was maintained at 0.01 Torr for 30 minutes to remove residualsolvent and excess thionyl chloride, leaving 12.1 g (94 percent) of1-hydroxycyclohexyl 4-(2-chloroformylethyl)carbonylphenyl ketone.

C. Covalent Bonding of Acylated Transorber to Cyclodextrin

A 250-ml, three-necked, round-bottomed reaction flask containing amagnetic stirring bar and fitted with a thermometer, condenser, andpressure-equalizing addition funnel equipped with a nitrogen inlet tubewas charged with 10 g (9.8 mmole) of β-cyclodextrin (AmericanMaize-Products Company, Hammond, Ind.), 31.6 g (98 mmoles) of1-hydroxycyclohexyl 4-(2-chloroformylethyl)carbonylphenyl ketone, and100 ml of N,N-dimethylformamide while being continuously flushed withnitrogen. The reaction mixture was heated to 50° C. and 0.5 ml oftriethylamine added. The reaction mixture was maintained at 50° C. foran hour and allowed to cool to ambient temperature. In this preparation,no attempt was made to isolate the product, a β-cyclodextrin to which anultraviolet radiation transorber had been covalently coupled (referredto hereinafter for convenience as β-cyclodextrin-transorber).

The foregoing procedure was repeated to isolate the product of thereaction. At the conclusion of the procedure as described, the reactionmixture was concentrated in a rotary evaporator to roughly 10 percent ofthe original volume. The residue was poured into ice water to whichsodium chloride then was added to force the product out of solution. Theresulting precipitate was isolated by filtration and washed with diethylether. The solid was dried under reduced pressure to give 24.8 g of awhite powder. In a third preparation, the residue remaining in therotary evaporator was placed on top of an approximately 7.5-cm columncontaining about 15 g of silica gel. The residue was eluted withN,N-dimethylformamide, with the eluant being monitored by means ofWhatman® Flexible-Backed TLC Plates (Catalog No. 05-713-161, FisherScientific, Pittsburgh, Pa.). The eluted product was isolated byevaporating the solvent. The structure of the product was verified bynuclear magnetic resonance analysis.

D. Association of Colorant with Cyclodextrin-Transorber-Preparation ofColored Composition

To a solution of 10 g (estimated to be about 3.6 mmole) ofβ-cyclodextrin-transorber in 150 ml of N,N-dimethylformamide in a 250-mlround-bottomed flask was added at ambient temperature 1.2 g (3.6 mmole)of Malachite Green oxalate (Aldrich Chemical Company, Inc., Milwaukee,Wis.), referred to hereinafter as Colorant A for convenience. Thereaction mixture was stirred with a magnetic stirring bar for one hourat ambient temperature. Most of the solvent then was removed in a rotaryevaporator and the residue was eluted from a silica gel column asalready described. The beta-cyclodextrin-transorber Colorant A inclusioncomplex moved down the column first, cleanly separating from both freeColorant A and beta-cyclodextrin-transorber. The eluant containing thecomplex was collected and the solvent removed in a rotary evaporator.The residue was subjected to a reduced pressure of 0.01 Torr to removeresidual solvent to yield a blue-green powder.

E. Mutation of Colored Composition

The beta-cyclodextrin-transorber Colorant A inclusion complex wasexposed to ultraviolet radiation from two different lamps, Lamps A andB. Lamp A was a 222-nanometer excimer lamp assembly organized in banksof four cylindrical lamps having a length of about 30 cm. The lamps werecooled by circulating water through a centrally located or inner tube ofthe lamp and, as a consequence, they operated at a relatively lowtemperature, i.e., about 50° C. The power density at the lamp's outersurface typically is in the range of from about 4 to about 20 joules persquare meter (J/m²). However, such range in reality merely reflects thecapabilities of current excimer lamp power supplies; in the future,higher power densities may be practical. The distance from the lamp tothe sample being irradiated was 4.5 cm. Lamp B was a 500-watt Hanoviamedium pressure mercury lamp (Hanovia Lamp Co., Newark, N.J.). Thedistance from Lamp B to the sample being irradiated was about 15 cm.

A few drops of an N,N-dimethylformamide solution of thebeta-cyclodextrin-transorber Colorant A inclusion complex were placed ona TLC plate and in a small polyethylene weighing pan. Both samples wereexposed to Lamp A and were decolorized (mutated to a colorless state) in15-20 seconds. Similar results were obtained with Lamp B in 30 seconds.

A first control sample consisting of a solution of Colorant A andbeta-cyclodextrin in N,N-dimethylformamide was not decolorized by LampA. A second control sample consisting of Colorant A and1-hydroxycyclohexyl phenyl ketone in N,N-dimethylformamide wasdecolorized by Lamp A within 60 seconds. On standing, however, the colorbegan to reappear within an hour.

To evaluate the effect of solvent on decolorization, 50 mg of thebeta-cyclodextrin-transorber Colorant A inclusion complex was dissolvedin 1 ml of solvent. The resulting solution or mixture was placed on aglass microscope slide and exposed to Lamp A for 1 minute. The rate ofdecolorization, i.e., the time to render the sample colorless, wasdirectly proportional to the solubility of the complex in the solvent,as summarized below.

                  TABLE 1                                                         ______________________________________                                                                   Decolorization                                     Solvent          Solubility                                                                              Time                                               ______________________________________                                        N,N-Dimethylformamide                                                                          Poor         1 minute                                        Dimethylsulfoxide                                                                              Soluble   <10 seconds                                        Acetone          Soluble   <10 seconds                                        Hexane           Insoluble --                                                 Ethyl Acetate    Poor         1 minute                                        ______________________________________                                    

Finally, 10 mg of the beta-cyclodextrin-transorber Colorant A inclusioncomplex were placed on a glass microscope slide and crushed with apestle. The resulting powder was exposed to Lamp A for 10 seconds. Thepowder turned colorless. Similar results were obtained with Lamp B, butat a slower rate.

EXAMPLE 2

Because of the possibility in the preparation of the colored compositiondescribed in the following examples for the acylated transorber acidchloride to at least partially occupy the cavity of the cyclodextrin, tothe partial or complete exclusion of colorant, a modified preparativeprocedure was carried out. Thus, this example describes the preparationof a beta-cyclodextrin molecular includant having (1) a colorant atleast partially included within the cavity of the cyclodextrin andassociated therewith by means of hydrogen bonds and/or van der Waalsforces, and (2) an ultraviolet radiation transorber covalently bonded tothe cyclodextrin substantially outside of the cavity of thecyclodextrin.

A. Association of Colorant with a Cyclodextrin

To a solution of 10.0 g (9.8 mmole) of beta-cyclodextrin in 150 ml ofN,N-dimethylformamide was added 3.24 g (9.6 mmoles) of Colorant A. Theresulting solution was stirred at ambient temperature for one hour. Thereaction solution was concentrated under reduced pressure in a rotaryevaporator to a volume about one-tenth of the original volume. Theresidue was passed over a silica gel column as described in Part C ofExample 1. The solvent in the eluant was removed under reduced pressurein a rotary evaporator to give 12.4 g of a blue-green powder,beta-cyclodextrin Colorant A inclusion complex.

B. Covalent Bonding of Acylated Transorber to Cyclodextrin ColorantInclusion Complex--Preparation of Colored Composition

A 250-ml, three-necked, round-bottomed reaction flask containing amagnetic stirring bar and fitted with a thermometer, condenser, andpressure-equalizing addition funnel equipped with a nitrogen inlet tubewas charged with 10 g (9.6 mmole) of beta-cyclodextrin Colorant Ainclusion complex, 31.6 g (98 mmoles) of 1-hydroxycyclohexyl4-(2-chloroformylethyl)carbonylphenyl ketone prepared as described inPart B of Example 1, and 150 ml of N,N-dimethylformamide while beingcontinuously flushed with nitrogen. The reaction mixture was heated to50° C. and 0.5 ml of triethylamine added. The reaction mixture wasmaintained at 50° C. for an hour and allowed to cool to ambienttemperature. The reaction mixture then was worked up as described inPart A, above, to give 14.2 g of beta-cyclodextrin-transorber Colorant Ainclusion complex, a blue-green powder.

C. Mutation of Colored Composition

The procedures described in Part E of Example 1 were repeated with thebeta-cyclodextrin-transorber Colorant A inclusion complex prepared inPart B, above, with essentially the same results.

EXAMPLE 3

This example describes a method of preparing an ultraviolet radiationtransorber, 2-[p-(2-methyllactoyl)phenoxy]ethyl1,3-dioxo-2-isoindolineacetate, designated phthaloylglycine-2959.

The following was admixed in a 250 ml, three-necked, round bottomedflask fitted with a Dean & Stark adapter with condenser and two glassstoppers: 20.5 g (0.1 mole) of the wavelength selective sensitizer,phthaloylglycine (Aldrich Chemical Co., Milwaukee, Wis.); 24.6 g (0.1mole) of the photoreactor, DARCUR 2959 (Ciba-Geigy, Hawthorne, N.Y.);100 ml of benzene (Aldrich Chemical Co., Milwaukee, Wis.); and 0.4 gp-toluenesulfonic acid (Aldrich Chemical Co., Milwaukee, Wis.). Themixture was heated at reflux for 3 hours after which time 1.8 ml ofwater was collected. The solvent was removed under reduced pressure togive 43.1 g of white powder. The powder was recrystallized from 30%ethyl acetate in hexane (Fisher) to yield 40.2 g (93%) of a whitecrystalline powder having a melting point of 153°-4° C. The reaction issummarized as follows: ##STR9##

The resulting product, designated phthaloylglycine-2959, had thefollowing physical parameters:

IR [NUJOL MULL]ν_(max) 3440, 1760, 1740, 1680, 1600 cm-1

1H NMR [CDCl3]∂ppm 1.64[s], 4.25[m], 4.49[m], 6.92[m], 7.25[m], 7.86[m],7.98[m], 8.06[m]ppm

EXAMPLE 4

This example describes a method of dehydrating the phthaloylglycine-2959produced in Example 3.

The following was admixed in a 250 ml round bottomed flask fitted with aDean & Stark adapter with condenser: 21.6 g (0.05 mole)phthaloylglycine-2959; 100 ml of anhydrous benzene (Aldrich ChemicalCo., Milwaukee, Wis.); and 0.1 g p-toluenesulfonic acid (AldrichChemical Co., Milwaukee, Wis.). The mixture was refluxed for 3 hours.After 0.7 ml of water had been collected in the trap, the solution wasthen removed under vacuum to yield 20.1 g (97%) of a white solid.However, analysis of the white solid showed that this reaction yieldedonly 15 to 20% of the desired dehydration product. The reaction issummarized as follows: ##STR10##

The resulting reaction product had the following physical parameters:

IR (NUJOL) ν_(max) 1617cm-1 (C═C--C═O)

EXAMPLE 5

This example describes the Nohr-MacDonald elimination reaction used todehydrate the phthaloylglycine-2959 produced in Example 3.

Into a 500 ml round bottomed flask were placed a stirring magnet, 20.0 g(0.048 mole) of the phthaloylglycine-2959, and 6.6 g (0.048 mole) ofanhydrous zinc chloride (Aldrich Chemical Co., Milwaukee, Wis.). 250 mlof anhydrous p-xylene (Aldrich Chemical Co., Milwaukee, Wis.) was addedand the mixture refluxed under argon atmosphere for two hours. Thereaction mixture was then cooled, resulting in a white precipitate whichwas collected. The white powder was then recrystallized from 20% ethylacetate in hexane to yield 18.1 g (95%) of a white powder. The reactionis summarized as follows: ##STR11##

The resulting reaction product had the following physical parameters:

Melting Point: 138° C. to 140° C.

Mass spectrum: m/e: 393 M+, 352, 326, 232, 160.

IR (KB) ν_(max) 1758, 1708, 1677, 1600 cm-1

1H NMR [DMSO]∂ppm 1.8(s), 2.6(s), 2.8 (d), 3.8 (d), 4.6 (m), 4.8 (m),7.3(m), 7.4 (m), 8.3 (m), and 8.6 (d)

13C NMR [DMSO]∂ppm 65.9 (CH2═)

EXAMPLE 6

This example describes a method of producing a beta-cyclodextrin havingdehydrated phthaloylglycine-2959 groups from Example 4 or 5 covalentlybonded thereto.

The following was admixed in a 100 ml round-bottomed flask: 5.0 g (4mmole) beta-cyclodextrin (American Maize Product Company, Hammond, Ind.)(designated beta-CD in the following reaction); 8.3 g (20 mmole)dehydrated phthaloylglycine-2959; 50 ml of anhydrous DMF; 20 ml ofbenzene; and 0.01 g p-tolulenesulfonyl chloride (Aldrich Chemical Co.,Milwaukee, Wis.). The mixture was chilled in a salt/ice bath and stirredfor 24 hours. The reaction mixture was poured into 150 ml of weak sodiumbicarbonate solution and extracted three times with 50 ml ethyl ether.The aqueous layer was then filtered to yield a white solid comprisingthe beta-cyclodextrin with phthaloylglycine-2959 group attached. A yieldof 9.4 g was obtained. Reverse phase TLC plate using a 50:50DMF:acetonitrile mixture showed a new product peak compared to thestarting materials. The reaction is summarized as follows: ##STR12##

The beta-cyclodextrin molecule has several primary alcohols andsecondary alcohols with which the phthaloylglycine-2959 can react. Theabove representative reaction only shows a single phthaloylglycine-2959molecule for illustrative purposes.

EXAMPLE 7

This example describes a method of associating a colorant and anultraviolet radiation transorber with a molecular includant. Moreparticularly, this example describes a method of associating thecolorant crystal violet with the molecular includant beta-cyclodextrincovalently bonded to the ultraviolet radiation transorber dehydratedphthaloylglycine-2959 of Example 6.

The following was placed in a 100 ml beaker: 4.0 g beta-cyclodextrinhaving a dehydrated phthaloylglycine-2959 group; and 50 ml of water. Thewater was heated to 70° C. at which point the solution became clear.Next, 0.9 g (2.4 mmole) crystal violet (Aldrich Chemical Company,Milwaukee, Wis.) was added to the solution, and the solution was stirredfor 20 minutes. Next, the solution was then filtered. The filtrand waswashed with the filtrate and then dried in a vacuum oven at 84° C. Aviolet-blue powder was obtained having 4.1 g (92%) yield. The resultingreaction product had the following physical parameters:

U.V. Spectrum DMF ν_(max) 610 nm (cf cv ν_(max) 604 nm)

EXAMPLE 8

This example describes a method of producing the ultraviolet radiationtransorber 4(4-hydroxyphenyl) butan-2-one-2959 (chloro substituted).

The following was admixed in a 250 ml round-bottomed flask fitted with acondenser and magnetic stir bar: 17.6 g (0.1 mole) of the wavelengthselective sensitizer, 4(4-hydroxyphenyl) butan-2-one (Aldrich ChemicalCompany, Milwaukee, Wis.); 26.4 g (0.1 mole) of the photoreactor, chlorosubstituted DARCUR 2959 (Ciba-Geigy Corporation, Hawthorne, N.Y.); 1.0ml of pyridine (Aldrich Chemical Company, Milwaukee, Wis.); and 100 mlof anhydrous tetrahydrofuran (Aldrich Chemical Company, Milwaukee,Wis.). The mixture was refluxed for 3 hours and the solvent partiallyremoved under reduced pressure (60% taken off). The reaction mixture wasthen poured into ice water and extracted with two 50 ml aliquots ofdiethyl ether. After drying over anhydrous magnesium sulfate and removalof solvent, 39.1 g of white solvent remained. Recrystallization of thepowder from 30% ethyl acetate in hexane gave 36.7 g (91%) of a whitecrystalline powder, having a melting point of 142°-3° C. The reaction issummarized in the following reaction: ##STR13##

The resulting reaction product had the following physical parameters:

IR [NUJOL MULL]ν_(max) 3460, 1760, 1700, 1620, 1600 cm-1

1H [CDCl3]∂ppm 1.62[s], 4.2[m], 4.5[m], 6.9[m]ppm

The ultraviolet radiation transorber produced in this example,4(4-hydroxyphenyl) butan-2-one-2959 (chloro substituted), may beassociated with beta-cyclodextrin and a colorant such as crystal violet,using the methods described above wherein 4(4-hydroxyphenyl)butan-2-one-2959 (chloro substituted) would be substituted for thedehydrated phthaloylglycine-2959.

EXAMPLE 9

Stabilizing activity of the radiation transorber

This example demonstrates the ability of the present invention tostabilize colorants against light. Victoria Pure Blue BO is admixed inacetonitrile with phthaloylglycine-2959. The compounds are summarized bythe following formulas: ##STR14## and dehydrated phthaloylglycine-2959:##STR15##

Solutions were prepared according to Table 2. The dye solutions werecarefully, uniformly spread on steel plates to a thickness ofapproximately 0.1 mm. The plates were then immediately exposed to amedium pressure 1200 watt high intensity quartz arc mercury dischargelamp (Conrad-Hanovia, Inc., Newark, N.J.) at a distance of 30 cm fromthe light. The mercury discharge light is a source of high intensity,broad spectrum light that is used in accelerated fading analyses. Table2 shows the results of the fade time with the various solutions. Fadetime is defined as the time until the dye became colorless to the nakedeye.

                  TABLE 2                                                         ______________________________________                                                       Victoria pure  Fade                                            Phthaloylglycine-2959                                                                        Blue BO        Time                                            ______________________________________                                         3 parts by weight                                                                           1 part by weight                                                                             2      min                                      10 parts by weight                                                                           1 part by weight                                                                             1 1/2  min                                      20 parts by weight                                                                           11 part by weight                                                                            30     sec                                      ______________________________________                                        Dehydrated     Victoria pure  Fade                                            Phthaloylglycine-2959                                                                        Blue BO        Time                                            ______________________________________                                         3 parts by weight                                                                           1 part by weight                                                                             4      min                                      10 parts by weight                                                                           1 part by weight                                                                             8      min                                      20 parts by weight                                                                           1 part by weight                                                                             >10    min                                      ______________________________________                                    

As can be seen in Table 2, when phthaloylglycine-2959 was admixed withVictoria Pure Blue BO, the dye faded when exposed to the mercurydwascharge light. However, when dehydrated phthaloylglycine-2959 wasadmixed with the Victoria Pure Blue BO at a ratio of 10 parts dehydratedphthaloylglycine-2959 to one part Victoria Pure Blue BO, there wasincreased stabilization of the dye to light. When the ratio was 20 partsdehydrated phthaloylglycine-2959 to one part Victoria Pure Blue BO, thedye was substantially stabilized to the mercury dwascharge light in thetime limits of the exposure.

EXAMPLE 10

To determine whether the hydroxy and the dehydroxy 2959 have thecapability to stabilize colorants the following experiment wasconducted. The compounds represented by the following formulas weretested as described below: ##STR16## 20 parts by weight of the hydroxyand the dehydroxy 2959 were admixed separately to one part by weight ofVictoria Pure Blue BO in acetonitrile. The dye solutions were cwerefullyuniformly spread on steel plates to a thickness of approximately 0.1 mm.The plates were then immediately exposed to a mercury discharge light ata distance of 30 cm from the light. The mercury discharge light is asource of high intensity, broad spectrum light that is used inaccelerated fading analyses. Table 3 shows the results of the fade timewith the various solutions. Fade time is defined as the time until thedye became colorless to the naked eye.

                  TABLE 3                                                         ______________________________________                                        Compound          Victoria Blue                                                                            Fade Time                                        ______________________________________                                        20 parts 2959 (Hydroxy)                                                                         1 part     <2 min                                           20 parts 2959 (Dehydroxy)                                                                       1 part     <2 min                                           None              1 part     <2 min                                           ______________________________________                                    

EXAMPLE 11

Stabilizing activity of the radiation transorber and a molecularincludant

This example demonstrates the capability of dehydratedphthaloylglycine-2959 bound to beta-cyclodextrin to stabilize dyesagainst light. The Victoria Pure Blue BO associated with the radiationtransorber, as discussed in the examples above, was tested to determineits capability to stabilize the associated dye against light emittedfrom a mercury discharge fight. In addition, the Victoria Pure Blue BOalone and Victoria Pure Blue BO admixed with beta cyclodextrin weretested as controls. The compositions tested were as follows:

1. Victoria Pure Blue BO only at a concentration of 10 mg/ml inacetonitrile.

2. Victoria Pure Blue BO included in beta cyclodextrin at aconcentration of 20 mg/ml in acetonitrile.

3. The Victoria Pure Blue BO included in beta cyclodextrin to which theradiation transorber (dehydrated phthaloylglycine-2959) is covalentlyattached at a concentration of 20 mg/ml in acetonitrile.

The protocol for testing the stabilizing qualities of the threecompositions is as follows: the dye solutions were carefully, uniformlyspread on steel plates to a thickness of approximately 0.1 mm. Theplates were then immediately exposed to a medium pressure 1200 watt highintensity quartz arc mercury discharge lamp (Conrad-Hanovia, Inc.,Newark, N.J.) at a distance of 30 cm from the lamp.

                  TABLE 4                                                         ______________________________________                                        Composition    Fade Time                                                      ______________________________________                                        1              5 sec                                                          2              5 sec                                                          3              >10 minutes.sup.a                                              ______________________________________                                         .sup.a There is a phase change after 10 minutes due to extreme heat      

As shown in Table 4, only composition number 3, the Victoria Pure BlueBO included in cyclodextrin with the radiation transorber covalentlyattached to the β-cyclodextrin was capable of stabilizing the dye underthe mercury discharge fight.

EXAMPLE 12

Preparation of epoxide intermediate of dehydrated phthaloylglycine-2959

The epoxide intermediate of dehydrated phthaloylglycine 2959 wasprepared according to the following reaction: ##STR17##

In a 250 ml, three-necked, round bottomed flask fitted with an additionfunnel, thermometer and magnetic stirrer was placed 30.0 g (0.076 mol)of the dehydrated phthaloylglycine-2959, 70 ml methanol and 20.1 mlhydrogen peroxide (30% solution). The reaction mixture was stirred andcooled in a water/ice bath to maintain a temperature in the range15°-20° C. 5.8 ml of a 6N NaOH solution was placed in the additionfunnel and the solution was slowly added to maintain the reactionmixture temperature of 15°-20° C. This step took about 4 minutes. Themixture was then stirred for 3 hours at about 20°-25° C. The reactionmixture was then poured into 90 ml of water and extracted with two 70 mlportions of ethyl ether. The organic layers were combined and washedwith 100 ml of water, dried with anhydrous MgSO₄, filtered, and theether removed on a rotary evaporator to yield a white solid (yield 20.3g, 65%). The IR showed the stretching of the C--O--C group and thematerial was used without further purification.

EXAMPLE 13

Attachment of epoxide intermediate to thiol cyclodextrin

The attachment of the epoxide intermediate of dehydratedphthaloylglycine 2959 was accomplished according to the followingreaction: ##STR18##

In a 250 ml 3-necked round bottomed flask fitted with a stopper and twoglass stoppers, all being wired with copper wire and attached to theflask with rubber bands, was placed 30.0 g (0.016 mol) thiolcyclodextrin and 100 ml of anhydrous dimethylformamide (DMF) (AldrichChemical Co., Milwaukee, Wis.). The reaction mixture was cooled in a icebath and 0.5 ml diisopropyl ethyl amine was added. Hydrogen sulfide wasbubbled into the flask and a positive pressure maintained for 3 hours.During the last hour, the reaction mixture was allowed to warm to roomtemperature.

The reaction mixture was flushed with argon for 15 minutes and thenpoured into 70 ml of water to which was then added 100 ml acetone. Awhite precipitate occurred and was filtered to yield 20.2 g (84.1%) of awhite powder which was used without further purification.

In a 250 ml round bottomed flask fitted with a magnetic stirrer andplaced in an ice bath was placed 12.7 (0.031 mol), 80 ml of anhydrousDMF (Aldrich Chemical Co., Milwaukee, Wis.) and 15.0 g (0.010 mol) thiolCD. After the reaction mixture was cooled, 0.5 ml of diisopropyl ethylamine was added and the reaction mixture stirred for 1 hour at 0° C. to5° C. followed by 2 hours at room temperature. The reaction mixture wasthen poured into 200 ml of ice water and a white precipitate formedimmediately. This was filtered and washed with acetone. The damp whitepowder was dried in a convection oven at 80° C. for 3 hours to yield awhite powder. The yield was 24.5 g (88%).

EXAMPLE 14

Insertion of Victoria Blue in the cyclodextrin cavity

In a 250 ml Erlenmeyer flask was placed a magnetic stirrer, 40.0 g(0.014 mol) of the compound produced in Example 13 and 100 ml water. Theflask was heated on a hot plate to 80° C. When the white cloudy mixturebecame clear, 7.43 g (0.016 mol) of Victoria Pure Blue BO powder wasthen added to the hot solution and stirred for 10 minutes then allowedto cool to 50° C. The contents were then filtered and washed with 20 mlof cold water.

The precipitate was then dried in a convention oven at 80° C. for 2hours to yield a blue powder 27.9 g (58.1%).

EXAMPLE 15

The preparation of a tosylated cyclodextrin with the dehydroxyphthaloylglycine 2959 attached thereto is performed by the followingreactions: ##STR19##

To a 500 ml 3-necked round bottomed flask fitted with a bubble tube,condenser and addition funnel, was placed 10 g (0.025 mole) of thedehydrated phthaloylglycine 2959 in 150 ml of anhydrousN,N-diethylformamide (Aldrich Chemical Co., Milwaukee, Wis.) cooled to0° C. in an ice bath and stirred with a magnetic stirrer. The synthesiswas repeated except that the flask was allowed to warm up to 60° C.using a warm water bath and the H₂ S pumped into the reaction flask tillthe stoppers started to move (trying to release the pressure). The flaskwas then stirred under these conditions for 4 hours. The saturatedsolution was kept at a positive pressure of H₂ S. The stoppers were helddown by wiring and rubber bands. The reaction mixture was then allowedto warm-up overnight. The solution was then flushed with argon for 30minutes and the reaction mixture poured onto 50 g of crushed ice andextracted three times (3×80 ml) with diethyl ether (Aldrich ChemicalCo., Milwaukee, Wis.).

The organic layers were condensed and washed with water and dried withMgSO₄. Removal of the solvent on a rotary evaporator gave 5.2 g of acrude product. The product was purified on a silica column using 20%ethyl acetate in hexane as eluant. 4.5 g of a white solid was obtained.

A tosylated cyclodextrin was prepared according to the followingreaction: ##STR20##

To a 100 ml round bottomed flask was placed 6.0 g β-cyclodextrin(American Maize Product Company), 10.0 g (0.05 mole) p-toluenesulfonylchloride (Aldrich Chemical Co., Milwaukee, Wis.), 50 ml of pH 10 buffersolution (Fisher). The resultant mixture was stirred at room temperaturefor 8 hours after which it was poured on ice (approximately 100 g) andextracted with diethyl ether. The aqueous layer was then poured into 50ml of acetone (Fisher) and the resultant, cloudy mixture filtered. Theresultant whim powder was then run through a sephadex column (AldrichChemical Co., Milwaukee, Wis.) using n-butanol, ethanol, and water(5:4:3 by volume) as eluant to yield a white powder. The yield was10.9%.

The degree of substitution of the white powder (tosylcyclodextrin) wasdetermined by ¹³ C NMR spectroscopy (DMF-d6) by comparing the ratio ofhydroxysubstituted carbons versus tosylated carbons, both at the 6position. When the 6-position carbon bears a hydroxy group, the NMRpeaks for each of the six carbon atoms are given in Table 5.

                  TABLE 5                                                         ______________________________________                                        Carbon Atom   NMR Peak (ppm)                                                  ______________________________________                                        1             101.8                                                           2             72.9                                                            3             72.3                                                            4             81.4                                                            5             71.9                                                            6             59.8                                                            ______________________________________                                    

The presence of the tosyl group shifts the NMR peaks of the 5-positionand 6-position carbon atoms to 68.8 and 69.5 ppm, respectively.

The degree of substitution was calculated by integrating the NMR peakfor the 6-position tosylated carbon, integrating the NMR peak for the6-position hydroxy-substituted carbon, and dividing the former by thelatter. The integrations yielded 23.6 and 4.1, respectively, and adegree of substitution of 5.9. Thus, the average degree of substitutionin this example is about 6.

The tosylated cyclodextrin with the dehydroxy phthaloylglycine 2959attached was prepared according to the following reaction: ##STR21##

To a 250 ml round bottomed flask was added 10.0 g (4-8 mole) oftosylated substituted cyclodextrin, 20.7 g (48 mmol) of thiol (mercaptodehydrated phthaloylglycine 2959) in 100 ml of DMF. The reaction mixturewas cooled to 0° C. in an ice bath and stirred using a magnetic stirrer.To the solution was slowly dropped in 10 ml of ethyl diisopropylamine(Aldrich Chemical Co., Milwaukee, Wis.) in 20 ml of DMF. The reactionwas kept at 0° C. for 8 hours with stirring. The reaction mixture wasextracted with diethyl ether. The aqueous layer was then treated with500 ml of acetone and the precipitate filtered and washed with acetone.The product was then run on a sephadex column using n-butanol, ethanol,and water (5:4:3 by volume) to yield a white powder. The yield was 16.7g.

The degree of substitution of the functionalized molecular includant wasdetermined as described above. In this case, the presence of thederivatized ultraviolet radiation transorber shifts the NMR peak of the6-position carbon atom to 63.1. The degree of substitution wascalculated by integrating the NMR peak for the 6-position substitutedcarbon, integrating the NMR peak for the 6-position hydroxy-substitutedcarbon, and dividing the former by the latter. The integrations yielded67.4 and 11.7, respectively, and a degree of substitution of 5.7. Thus,the average degree of substitution in this example is about 6. Thereaction above shows the degree of substitution to be "n". Although nrepresents the value of substitution on a single cyclodextrin, andtherefore, can be from 0 to 24, it is to be understood that the averagedegree of substitution is about 6.

EXAMPLE 16

The procedure of Example 15 was repeated, except that the amounts ofβ-cyclodextrin and p-toluenesulfonic acid (Aldrich) were 6.0 g and 5.0g, respectively. In this case, the degree of substitution of thecyclodextrin was found to be about 3.

EXAMPLE 17

The procedure of Example 15 was repeated, except that the derivatizedmolecular includant of Example 16 was employed in place of that fromExample 15. The average degree of substitution of the functionalizedmolecular includant was found to be about 3.

EXAMPLE 18

This example describes the preparation of a colored composition whichincludes a mutable colorant and the functionalized molecular includantfrom Example 15.

In a 250-ml Erlenmeyer flask containing a magnetic stirring bar wasplaced 20.0 g (5.4 mmoles) of the functionalized molecular includantobtained in Example 15 and 100 g of water. The water was heated to 80°C., at which temperature a clear solution was obtained. To the solutionwas added slowly, with stirring, 3.1 g (6.0 mmoles) of Victoria PureBlue BO (Aldrich). A precipitate formed which was removed from the hotsolution by filtration. The precipitate was washed with 50 ml of waterand dried to give 19.1 g (84 percent) of a blue powder, a coloredcomposition consisting of a mutable colorant, Victoria Pure Blue BO, anda molecular includant having covalently coupled to it an average ofabout six ultraviolet radiation transorber molecules per molecularincludant molecule.

EXAMPLE 19

The procedure of Example 18 was repeated, except that the functionalizedmolecular includant from Example 17 was employed in place of that fromExample 15.

EXAMPLE 20

This example describes mutation or decolorization rates for thecompositions of Examples 7 (wherein the beta-cyclodextrin has dehydratedphthaloyl glycine-2959 from Example 4 covalently bonded thereto), 18 and19.

In each case, approximately 10 mg of the composition was placed on asteel plate (Q-Panel Company, Cleveland, Ohio). Three drops (about 0.3ml) of acetonitrile (Burdick & Jackson, Muskegon, Mich.) was placed ontop of the composition and the two materials were quickly mixed with aspatula and spread out on the plate as a thin film. Within 5-10 secondsof the addition of the acetonitrile, each plate was exposed to theradiation from a 222-nanometer excimer lamp assembly. The assemblyconsisted of a bank of four cylindrical lamps having a length of about30 cm. The lamps were cooled by circulating water through a centrallylocated or inner tube of the lamp and, as a consequence, they operatedat a relatively low temperature, i.e., about 50° C. The power density atthe lamp's outer surface typically was in the range of from about 4 toabout 20 joules per square meter (J/m²). However, such range in realitymerely reflects the capabilities of current excimer lamp power supplies;in the future, higher power densities may be practical. The distancefrom the lamp to the sample being irradiated was 4.5 cm. The time foreach film to become colorless to the eye was measured. The results aresummarized in Table 6.

                  TABLE 6                                                         ______________________________________                                        Decolorization Times for Various Compositions                                 Composition Decolorization Times (Seconds)                                    ______________________________________                                        Example 18  1                                                                 Example 19  3-4                                                               Example 7   7-8                                                               ______________________________________                                    

While the data in Table 6 demonstrate the clear superiority of thecolored compositions of the present invention, such data were plotted asdegree of substitution versus decolorization time. The plot is shown inFIG. 3. FIG. 3 not only demonstrates the significant improvement of thecolored compositions of the present invention when compared withcompositions having a degree of substitution less than three, but alsoindicates that a degree of substitution of about 6 is about optimum.That is, the figure indicates that little if any improvement indecolonization time would be achieved with degrees of substitutiongreater than about 6.

EXAMPLE 21

This example describes the preparation of a complex consisting of amutable colorant and the derivatized molecular includant of Example 15.

The procedure of Example 18 was repeated, except that the functionalizedmolecular includant of Example 15 was replaced with 10 g (4.8 mmoles) ofthe derivatized molecular includant of Example 15 and the amount ofVictoria Pure Blue BO was reduced to 2.5 g (4.8 mmoles). The yield ofwashed solid was 10.8 g (86 percent) of a mutable colorant associatedwith the β-cyclodextrin having an average of six tosyl groups permolecule of molecular includant.

EXAMPLE 22

This example describes the preparation of a colored composition whichincludes a mumble colorant and a functionalized molecular includant.

The procedure of preparing a functionalized molecular includant ofExample 15 was repeated, except that the tosylated B-cyclodextrin wasreplaced with 10 g (3.8 mmoles) of the complex obtained in Example 21and the amount of the derivatized ultraviolet radiation transorberprepared in Example 15 was 11.6 g (27 mmoles). The amount of coloredcomposition obtained was 11.2 g (56 percent). The average degree ofsubstitution was determined as described above, and was found to be 5.9,or about 6.

EXAMPLE 23

The two compounds represented by the following formulas were tested fortheir ability to stabilize Victoria Pure Blue BO: ##STR22##

Hydroxy Compound

This example further demonstrates the ability of the present inventionto stabilize colorants against light. The two compounds containingVictoria Pure Blue BO as an includant in the cyclodextrin cavity weretested for fight fastness under a medium pressure mercury dischargelamp. 100 mg of each compound was dissolved in 20 ml of acetonitrile andwas uniformly spread on steel plates to a thickness of approximately 0.1mm. The plates were then immediately exposed to a medium pressure 1200watt high intensity quartz arc mercury discharge lamp (Conrad-Hanovia,Inc., Newark, N.J.) at a distance of 30 cm from the lamp. The lightfastness results of these compounds are summarized in Table 7.

                  TABLE 7                                                         ______________________________________                                        Cyclodextrin Compound  Fade Time                                              ______________________________________                                        Dehydroxy Compound     >10 min.sup.a                                          Hydroxy Compound       <20 sec                                                ______________________________________                                         .sup.a There is a phase change after 10 minutes due to extreme heat      

EXAMPLE 24

This example describes the preparation of films consisting of colorant,ultraviolet radiation transorber, and thermoplastic polymer. Thecolorant and ultraviolet radiation transorber were ground separately ina mortar. The desired amounts of the ground components were weighed andplaced in an aluminum pan, along with a weighed amount of athermoplastic polymer. The pan was placed on a hot plate set at 150° C.and the mixture in the pan was stirred until molten. A few drops of themolten mixture were poured onto a steel plate and spread into a thinfilm by means of a glass microscope slide. Each steel plate was 3×5inches (7.6 cm×12.7 cm) and was obtained from Q-Panel Company,Cleveland, Ohio. The film on the steel plate was estimated to have athickness of the order of 10-20 micrometers.

In every instance, the colorant was Malachite Green oxalate (AldrichChemical Company, Inc., Milwaukee, Wis.), referred to hereinafter asColorant A for convenience. The ultraviolet radiation transorber("UVRT") consisted of one or more of Irgacure® 500 ("UVRT A"), Irgacure®651 ("UVRT B"), and Irgacure® 907 ("UVRT C"), each of which wasdescribed earlier and is available from Ciba-Geigy Corporation,Hawthorne, N.Y. The polymer was one of the following: anepichlorohydrin-bisphenol A epoxy resin ("Polymer A"), Epon® 1004F(Shell Oil Company, Houston, Tex.); a poly(ethylene glycol) having aweight-average molecular weight of about 8,000 ("Polymer B"), Carbowax8000 (Aldrich Chemical Company); and a poly(ethylene glycol) having aweight-average molecular weight of about 4,600 ("Polymer C"), Carbowax4600 (Aldrich Chemical Company). A control film was prepared whichconsisted only of colorant and polymer. The compositions of the filmsare summarized in Table 8.

                  TABLE 8                                                         ______________________________________                                        Compositions of Films Containing                                              Colorant and Ultraviolet Radiation Transorber ("UVRT")                        Colorant            UVRT          Polymer                                     Film    Type   Parts    Type Parts  Type Parts                                ______________________________________                                        A       A      1        A    6      A    90                                                           C    4                                                B       A      1        A    12     A    90                                                           C    8                                                C       A      1        A    18     A    90                                                           C    12                                               D       A      1        A    6      A    90                                                           B    4                                                E       A      1        B    30     A    70                                   F       A      1        --   --     A    100                                  G       A      1        A    6      B    90                                                           C    4                                                H       A      1        B    10     C    90                                   ______________________________________                                    

While still on the steel plate, each film was exposed to ultravioletradiation. In each case, the steel plate having the film sample on itssurface was placed on a moving conveyor belt having a variable speedcontrol. Three different ultraviolet radiation sources, or lamps, wereused. Lamp A was a 222-nanometer excimer lamp and Lamp B was a308-nanometer excimer lamp, as already described. Lamp C was a fusionlamp system having a "D" bulb (Fusion Systems Corporation, Rockville,Md.). The excimer lamps were organized in banks of four cylindricallamps having a length of about 30 cm, with the lamps being orientednormal to the direction of motion of the belt. The lamps were cooled bycirculating water through a centrally located or inner tube of the lampand, as a consequence, they operated at a relatively low temperature,i.e., about 50° C. The power density at the lamp's outer surfacetypically is in the range of from about 4 to about 20 joules per squaremeter (J/m²).

However, such range in reality merely reflects the capabilities ofcurrent excimer lamp power supplies; in the future, higher powerdensities may be practical. With Lamps A and B, the distance from thelamp to the film sample was 4.5 cm and the belt was set to move at 20ft/min (0.1 m/sec). With Lamp C, the belt speed was 14 ft/min (0.07m/sec) and the lamp-to-sample distance was 10 cm. The results ofexposing the film samples to ultraviolet radiation are summarized inTable 9. Except for Film F, the table records the number of passes undera lamp which were required in order to render the film colorless. ForFilm F, the table records the number of passes tried, with the film ineach case remaining colored (no change).

                  TABLE 9                                                         ______________________________________                                        Results of Exposing Films Containing                                          Colorant and Ultraviolet Radiation Transorber (UVRT)                          to Ultraviolet Radiation                                                      Excimer Lamp                                                                  Film   Lamp A        Lamp B   Fusion Lamp                                     ______________________________________                                        A      3             3        15                                              B      2             3        10                                              C      1             3        10                                              D      1             1        10                                              E      1             1         1                                              F      5             5        10                                              G      3             --       10                                              H      3             --       10                                              ______________________________________                                    

EXAMPLE 25

This Example demonstrates that the 222 nanometer excimer lampsillustrated in FIG. 4 produce uniform intensity readings on a surface ofa substrate 5.5 centimeters from the lamps, at the numbered locations,in an amount sufficient to mutate the colorant in the compositions ofthe present invention which are present on the surface of the substrate.The lamp 10 comprises a lamp housing 15 with four excimer lamp bulbs 20positioned in parallel, the excimer lamp bulbs 20 are approximately 30cm in length. The lamps are cooled by circulating water through acentrally located or inner tube (not shown) and, as a consequence, thelamps are operated at a relatively low temperature, i.e., about 50° C.The power density at the lamp's outer surface typically is in the rangeof from about 4 to about 20 joules per square meter (J/m²).

Table 10 summarizes the intensity readings which were obtained by ameter located on the surface of the substrate. The readings numbered 1,4, 7, and 10 were located approximately 7.0 centimeters from the leftend of the column as shown in FIG. 4. The readings numbered 3, 6, 9, and12 were located approximately 5.5 centimeters from the right end of thecolumn as shown in FIG. 4. The readings numbered 2, 5, 8, and 11 werecentrally located approximately 17.5 centimeters from each end of thecolumn as shown in FIG. 4.

                  TABLE 10                                                        ______________________________________                                        Background (μW)                                                                           Reading (mW/cm.sup.2)                                          ______________________________________                                        24.57          9.63                                                           19.56          9.35                                                           22.67          9.39                                                           19.62          9.33                                                           17.90          9.30                                                           19.60          9.30                                                           21.41          9.32                                                           17.91          9.30                                                           23.49          9.30                                                           19.15          9.36                                                           17.12          9.35                                                           21.44          9.37                                                           ______________________________________                                    

EXAMPLE 26

This Example demonstrates that the 222 nanometer excimer lampsillustrated in FIG. 5 produce uniform intensity readings on a surface ofa substrate 5.5 centimeters from the lamps, at the numbered locations,in an amount sufficient to mutate the colorant in the compositions ofthe present invention which are present on the surface of the substrate.The excimer lamp 10 comprises a lamp housing 15 with four excimer lampbulbs 20 positioned in parallel, the excimer lamp bulbs 20 areapproximately 30 cm in length. The lamps are cooled by circulating waterthrough a centrally located or inner tube (not shown) and, as aconsequence, the lamps are operated at a relatively low temperature,i.e., about 50° C. The power density at the lamp's outer surfacetypically is in the range of from about 4 to about 20 joules per squaremeter (J/m²).

Table 11 summarizes the intensity readings which were obtained by ameter located on the surface of the substrate. The readings numbered 1,4, and 7 were located approximately 7.0 centimeters from the left end ofthe columns as shown in FIG. 5. The readings numbered 3, 6, and 9 werelocated approximately 5.5 centimeters from the fight end of the columnsas shown in FIG. 5. The readings numbered 2, 5, 8 were centrally locatedapproximately 17.5 centimeters from each end of the columns as shown inFIG. 5.

                  TABLE 11                                                        ______________________________________                                        Background (μW)                                                                           Reading (mW/cm.sup.2)                                          ______________________________________                                        23.46          9.32                                                           16.12          9.31                                                           17.39          9.32                                                           20.19          9.31                                                           16.45          9.29                                                           20.42          9.31                                                           18.33          9.32                                                           15.50          9.30                                                           20.90          9.34                                                           ______________________________________                                    

EXAMPLE 27

This Example demonstrates the intensity produced by the 222 nanometerexcimer lamps illustrated in FIG. 6, on a surface of a substrate, as afunction of the distance of the surface from the lamps, the intensitybeing sufficient to mutate the colorant in the compositions of thepresent invention which are present on the surface of the substrate. Theexcimer lamp 10 comprises a lamp housing 15 with four excimer lamp bulbs20 positioned in parallel, the excimer lamp bulbs 20 are approximately30 cm in length. The lamps are cooled by circulating water through acentrally located or inner tube (not shown) and, as a consequence, thelamps are operated at a relatively low temperature, i.e., about 50° C.The power density at the lamp's outer surface typically is in the rangeof from about 4 to about 20 joules per square meter (J/m²).

Table 12 summarizes the intensity readings which were obtained by ameter located on the surface of the substrate at position 1 as shown inFIG. 6. Position 1 was centrally located approximately 17 centimetersfrom each end of the column as shown in FIG. 6.

                  TABLE 12                                                        ______________________________________                                        Distance (cm)                                                                             Background (μW)                                                                         Reading (mW/cm.sup.2)                                ______________________________________                                        5.5         18.85        9.30                                                 6.0         15.78        9.32                                                 10          18.60        9.32                                                 15          20.90        9.38                                                 20          21.67        9.48                                                 25          19.86        9.69                                                 30          22.50        11.14                                                35          26.28        9.10                                                 40          24.71        7.58                                                 50          26.95        5.20                                                 ______________________________________                                    

Having thus described the invention, numerous changes and modificationshereof will be readily apparent to those having ordinary skill in theart, without departing from the spirit or scope of the invention.

What is claimed is:
 1. A recording medium comprising a substrate and arecording layer disposed thereon, the recording layer comprising acolored composition comprising a colorant and a radiation transorber,the colorant being mutable upon exposure of the composition toultraviolet radiation, wherein the radiation transorber is selected from##STR23##
 2. A recording medium comprising a substrate and a coloredcomposition contained therein, the colored composition comprising acolorant and a radiation transorber, the colorant being mutable uponexposure of the composition to ultraviolet radiation, wherein theradiation transorber is selected from ##STR24##
 3. A method of recordinginformation onto a recording medium comprising, selectively irradiatingportions of a layer of a colored composition comprising a colorant and aradiation transorber with sufficient ultraviolet radiation to mutate thecolor of the colorant at the irradiated portions, wherein the radiationtransorber is selected from ##STR25##
 4. A method of reading informationfrom a recording medium comprising a layer of a colored compositioncomprising a colorant and a radiation transorber, wherein the radiationtransorber is selected from ##STR26## the method comprising:sequentially illuminating portions of the layer with non-mutatingradiation; anddetecting the radiation reflected by the illuminatedportions.
 5. An optically recordable disk comprising a disk body havinga recording layer formed therewith, the recording layer comprising amutable colored composition comprising a colorant and a radiationtransorber, selected portions of the colored composition being mutableupon exposure to mutating radiation while adjacent portions which arenot exposed to mutating radiation are not mutated, the mutated andnon-mutated portions having different light reflectivities, and whereinthe radiation transorber is selected from ##STR27##
 6. An opticallyreadable disk comprising a disk body having a recording layer formedtherewith, the recording layer comprising a mutable colored compositioncomprising a colorant and a radiation transorber, the recording layercomprising regions where the colorant has been mutated and regions wherethe colorant has not been mutated, the mutated and non-mutated portionshaving different light reflectivities, the regions of mutated andnon-mutated colorant representing digitally encoded signals and whereinthe radiation transorber is selected from ##STR28##